14.7 Date and Time Functions (original) (raw)

This section describes the functions that can be used to manipulate temporal values. SeeSection 13.2, “Date and Time Data Types”, for a description of the range of values each date and time type has and the valid formats in which values may be specified.

Table 14.11 Date and Time Functions

Name	Description
ADDDATE()	Add time values (intervals) to a date value
ADDTIME()	Add time
CONVERT_TZ()	Convert from one time zone to another
CURDATE()	Return the current date
CURRENT_DATE(), CURRENT_DATE	Synonyms for CURDATE()
CURRENT_TIME(), CURRENT_TIME	Synonyms for CURTIME()
CURRENT_TIMESTAMP(), CURRENT_TIMESTAMP	Synonyms for NOW()
CURTIME()	Return the current time
DATE()	Extract the date part of a date or datetime expression
DATE_ADD()	Add time values (intervals) to a date value
DATE_FORMAT()	Format date as specified
DATE_SUB()	Subtract a time value (interval) from a date
DATEDIFF()	Subtract two dates
DAY()	Synonym for DAYOFMONTH()
DAYNAME()	Return the name of the weekday
DAYOFMONTH()	Return the day of the month (0-31)
DAYOFWEEK()	Return the weekday index of the argument
DAYOFYEAR()	Return the day of the year (1-366)
EXTRACT()	Extract part of a date
FROM_DAYS()	Convert a day number to a date
FROM_UNIXTIME()	Format Unix timestamp as a date
GET_FORMAT()	Return a date format string
HOUR()	Extract the hour
LAST_DAY	Return the last day of the month for the argument
LOCALTIME(), LOCALTIME	Synonym for NOW()
LOCALTIMESTAMP, LOCALTIMESTAMP()	Synonym for NOW()
MAKEDATE()	Create a date from the year and day of year
MAKETIME()	Create time from hour, minute, second
MICROSECOND()	Return the microseconds from argument
MINUTE()	Return the minute from the argument
MONTH()	Return the month from the date passed
MONTHNAME()	Return the name of the month
NOW()	Return the current date and time
PERIOD_ADD()	Add a period to a year-month
PERIOD_DIFF()	Return the number of months between periods
QUARTER()	Return the quarter from a date argument
SEC_TO_TIME()	Converts seconds to 'hh:mm:ss' format
SECOND()	Return the second (0-59)
STR_TO_DATE()	Convert a string to a date
SUBDATE()	Synonym for DATE_SUB() when invoked with three arguments
SUBTIME()	Subtract times
SYSDATE()	Return the time at which the function executes
TIME()	Extract the time portion of the expression passed
TIME_FORMAT()	Format as time
TIME_TO_SEC()	Return the argument converted to seconds
TIMEDIFF()	Subtract time
TIMESTAMP()	With a single argument, this function returns the date or datetime expression; with two arguments, the sum of the arguments
TIMESTAMPADD()	Add an interval to a datetime expression
TIMESTAMPDIFF()	Return the difference of two datetime expressions, using the units specified
TO_DAYS()	Return the date argument converted to days
TO_SECONDS()	Return the date or datetime argument converted to seconds since Year 0
UNIX_TIMESTAMP()	Return a Unix timestamp
UTC_DATE()	Return the current UTC date
UTC_TIME()	Return the current UTC time
UTC_TIMESTAMP()	Return the current UTC date and time
WEEK()	Return the week number
WEEKDAY()	Return the weekday index
WEEKOFYEAR()	Return the calendar week of the date (1-53)
YEAR()	Return the year
YEARWEEK()	Return the year and week

Here is an example that uses date functions. The following query selects all rows with a datecol value from within the last 30 days:

mysql> SELECT something FROM tbl_name
    -> WHERE DATE_SUB(CURDATE(),INTERVAL 30 DAY) <= date_col;

The query also selects rows with dates that lie in the future.

Functions that expect date values usually accept datetime values and ignore the time part. Functions that expect time values usually accept datetime values and ignore the date part.

Functions that return the current date or time each are evaluated only once per query at the start of query execution. This means that multiple references to a function such asNOW() within a single query always produce the same result. (For our purposes, a single query also includes a call to a stored program (stored routine, trigger, or event) and all subprograms called by that program.) This principle also applies to CURDATE(),CURTIME(),UTC_DATE(),UTC_TIME(),UTC_TIMESTAMP(), and to any of their synonyms.

The CURRENT_TIMESTAMP(),CURRENT_TIME(),CURRENT_DATE(), andFROM_UNIXTIME() functions return values in the current session time zone, which is available as the session value of the time_zone system variable. In addition,UNIX_TIMESTAMP() assumes that its argument is a datetime value in the session time zone. SeeSection 7.1.15, “MySQL Server Time Zone Support”.

Some date functions can be used with “zero” dates or incomplete dates such as '2001-11-00', whereas others cannot. Functions that extract parts of dates typically work with incomplete dates and thus can return 0 when you might otherwise expect a nonzero value. For example:

mysql> SELECT DAYOFMONTH('2001-11-00'), MONTH('2005-00-00');
        -> 0, 0

Other functions expect complete dates and returnNULL for incomplete dates. These include functions that perform date arithmetic or that map parts of dates to names. For example:

mysql> SELECT DATE_ADD('2006-05-00',INTERVAL 1 DAY);
        -> NULL
mysql> SELECT DAYNAME('2006-05-00');
        -> NULL

Several functions are strict when passed aDATE() function value as their argument and reject incomplete dates with a day part of zero:CONVERT_TZ(),DATE_ADD(),DATE_SUB(),DAYOFYEAR(),TIMESTAMPDIFF(),TO_DAYS(),TO_SECONDS(),WEEK(),WEEKDAY(),WEEKOFYEAR(),YEARWEEK().

Fractional seconds for TIME,DATETIME, and TIMESTAMP values are supported, with up to microsecond precision. Functions that take temporal arguments accept values with fractional seconds. Return values from temporal functions include fractional seconds as appropriate.

ADDDATE(date,INTERVAL_expr_ unit),ADDDATE(date,days)
When invoked with the INTERVAL form of the second argument, ADDDATE() is a synonym for DATE_ADD(). The related function SUBDATE() is a synonym for DATE_SUB(). For information on the INTERVAL unit argument, seeTemporal Intervals.

mysql> SELECT DATE_ADD('2008-01-02', INTERVAL 31 DAY);  
        -> '2008-02-02'  
mysql> SELECT ADDDATE('2008-01-02', INTERVAL 31 DAY);  
        -> '2008-02-02'

When invoked with the days form of the second argument, MySQL treats it as an integer number of days to be added to expr.

mysql> SELECT ADDDATE('2008-01-02', 31);  
        -> '2008-02-02'

This function returns NULL if_date_ or_days_ is NULL.

ADDTIME(expr1,expr2)
ADDTIME() adds_expr2_ to_expr1_ and returns the result.expr1 is a time or datetime expression, and expr2 is a time expression. Returns NULL if_expr1orexpr2_ is NULL.
Beginning with MySQL 8.0.28, the return type of this function and of the SUBTIME() function is determined as follows:
- If the first argument is a dynamic parameter (such as in a prepared statement), the return type isTIME.
- Otherwise, the resolved type of the function is derived from the resolved type of the first argument.

mysql> SELECT ADDTIME('2007-12-31 23:59:59.999999', '1 1:1:1.000002');  
        -> '2008-01-02 01:01:01.000001'  
mysql> SELECT ADDTIME('01:00:00.999999', '02:00:00.999998');  
        -> '03:00:01.999997'

CONVERT_TZ(dt,from_tz,to_tz)
CONVERT_TZ() converts a datetime value dt from the time zone given by fromtz to the time zone given by totz and returns the resulting value. Time zones are specified as described inSection 7.1.15, “MySQL Server Time Zone Support”. This function returnsNULL if any of the arguments are invalid, or if any of them are NULL.
On 32-bit platforms, the supported range of values for this function is the same as for theTIMESTAMP type (seeSection 13.2.1, “Date and Time Data Type Syntax”, for range information). On 64-bit platforms, beginning with MySQL 8.0.28, the maximum supported value is '3001-01-18 23:59:59.999999' UTC.
Regardless of platform or MySQL version, if the value falls out of the supported range when converted from_fromtz_ to UTC, no conversion occurs.

mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','GMT','MET');  
        -> '2004-01-01 13:00:00'  
mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','+00:00','+10:00');  
        -> '2004-01-01 22:00:00'

CURDATE()
Returns the current date as a value in'_`YYYY-MM-DD`_' or_YYYYMMDD_ format, depending on whether the function is used in string or numeric context.

mysql> SELECT CURDATE();  
        -> '2008-06-13'  
mysql> SELECT CURDATE() + 0;  
        -> 20080613

CURRENT_DATE,CURRENT_DATE()
CURRENT_DATE andCURRENT_DATE() are synonyms forCURDATE().
CURRENT_TIME,CURRENT_TIME([fsp])
CURRENT_TIME andCURRENT_TIME() are synonyms forCURTIME().
CURRENT_TIMESTAMP,CURRENT_TIMESTAMP([fsp])
CURRENT_TIMESTAMP andCURRENT_TIMESTAMP() are synonyms for NOW().
CURTIME([fsp])
Returns the current time as a value in_'hh:mm:ss'_ or_hhmmss_ format, depending on whether the function is used in string or numeric context. The value is expressed in the session time zone.
If the fsp argument is given to specify a fractional seconds precision from 0 to 6, the return value includes a fractional seconds part of that many digits.

mysql> SELECT CURTIME();  
+-----------+  
| CURTIME() |  
+-----------+  
| 19:25:37  |  
+-----------+  
mysql> SELECT CURTIME() + 0;  
+---------------+  
| CURTIME() + 0 |  
+---------------+  
|        192537 |  
+---------------+  
mysql> SELECT CURTIME(3);  
+--------------+  
| CURTIME(3)   |  
+--------------+  
| 19:25:37.840 |  
+--------------+

DATE(expr)
Extracts the date part of the date or datetime expression_expr_. ReturnsNULL if expr isNULL.

mysql> SELECT DATE('2003-12-31 01:02:03');  
        -> '2003-12-31'

DATEDIFF(expr1,expr2)
DATEDIFF() returns_expr1_ −_expr2_ expressed as a value in days from one date to the other. expr1 and expr2 are date or date-and-time expressions. Only the date parts of the values are used in the calculation.

mysql> SELECT DATEDIFF('2007-12-31 23:59:59','2007-12-30');  
        -> 1  
mysql> SELECT DATEDIFF('2010-11-30 23:59:59','2010-12-31');  
        -> -31

This function returns NULL if_expr1_ or_expr2_ is NULL.

DATE_ADD(date,INTERVAL_expr_ unit),DATE_SUB(date,INTERVAL_expr_ unit)
These functions perform date arithmetic. The_date_ argument specifies the starting date or datetime value.expr is an expression specifying the interval value to be added or subtracted from the starting date. expr is evaluated as a string; it may start with a - for negative intervals. unit is a keyword indicating the units in which the expression should be interpreted.
For more information about temporal interval syntax, including a full list of unit specifiers, the expected form of the expr argument for each unit value, and rules for operand interpretation in temporal arithmetic, seeTemporal Intervals.
The return value depends on the arguments:
- If date isNULL, the function returnsNULL.
- DATE if the_date_ argument is aDATE value and your calculations involve only YEAR,MONTH, and DAY parts (that is, no time parts).
- (MySQL 8.0.28 and later:)TIME if the_date_ argument is aTIME value and the calculations involve only HOURS, MINUTES, and SECONDS parts (that is, no date parts).
- DATETIME if the first argument is a DATETIME (orTIMESTAMP) value, or if the first argument is a DATE and the unit value usesHOURS, MINUTES, orSECONDS, or if the first argument is of type TIME and the_unit_ value usesYEAR, MONTH, orDAY.
- (MySQL 8.0.28 and later:) If the first argument is a dynamic parameter (for example, of a prepared statement), its resolved type isDATE if the second argument is an interval that contains some combination ofYEAR, MONTH, orDAY values only; otherwise, its type isDATETIME.
- String otherwise (typeVARCHAR).
  Note
  In MySQL 8.0.22 through 8.0.27, when used in prepared statements, these functions returnedDATETIME values regardless of argument types. (Bug #103781)
  To ensure that the result isDATETIME, you can useCAST() to convert the first argument to DATETIME.

mysql> SELECT DATE_ADD('2018-05-01',INTERVAL 1 DAY);  
        -> '2018-05-02'  
mysql> SELECT DATE_SUB('2018-05-01',INTERVAL 1 YEAR);  
        -> '2017-05-01'  
mysql> SELECT DATE_ADD('2020-12-31 23:59:59',  
    ->                 INTERVAL 1 SECOND);  
        -> '2021-01-01 00:00:00'  
mysql> SELECT DATE_ADD('2018-12-31 23:59:59',  
    ->                 INTERVAL 1 DAY);  
        -> '2019-01-01 23:59:59'  
mysql> SELECT DATE_ADD('2100-12-31 23:59:59',  
    ->                 INTERVAL '1:1' MINUTE_SECOND);  
        -> '2101-01-01 00:01:00'  
mysql> SELECT DATE_SUB('2025-01-01 00:00:00',  
    ->                 INTERVAL '1 1:1:1' DAY_SECOND);  
        -> '2024-12-30 22:58:59'  
mysql> SELECT DATE_ADD('1900-01-01 00:00:00',  
    ->                 INTERVAL '-1 10' DAY_HOUR);  
        -> '1899-12-30 14:00:00'  
mysql> SELECT DATE_SUB('1998-01-02', INTERVAL 31 DAY);  
        -> '1997-12-02'  
mysql> SELECT DATE_ADD('1992-12-31 23:59:59.000002',  
    ->            INTERVAL '1.999999' SECOND_MICROSECOND);  
        -> '1993-01-01 00:00:01.000001'

When adding a MONTH interval to aDATE or DATETIME value, and the resulting date includes a day that does not exist in the given month, the day is adjusted to the last day of the month, as shown here:

mysql> SELECT DATE_ADD('2024-03-30', INTERVAL 1 MONTH) AS d1,  
     >        DATE_ADD('2024-03-31', INTERVAL 1 MONTH) AS d2;  
+------------+------------+  
| d1         | d2         |  
+------------+------------+  
| 2024-04-30 | 2024-04-30 |  
+------------+------------+  
1 row in set (0.00 sec)

DATE_FORMAT(date,format)
Formats the date value according to the format string. If either argument is NULL, the function returnsNULL.
The specifiers shown in the following table may be used in the_format_ string. The% character is required before format specifier characters. The specifiers apply to other functions as well: STR_TO_DATE(),TIME_FORMAT(),UNIX_TIMESTAMP().

Specifier	Description
%a	Abbreviated weekday name (Sun..Sat)
%b	Abbreviated month name (Jan..Dec)
%c	Month, numeric (0..12)
%D	Day of the month with English suffix (0th,1st, 2nd,3rd, …)
%d	Day of the month, numeric (00..31)
%e	Day of the month, numeric (0..31)
%f	Microseconds (000000..999999)
%H	Hour (00..23)
%h	Hour (01..12)
%I	Hour (01..12)
%i	Minutes, numeric (00..59)
%j	Day of year (001..366)
%k	Hour (0..23)
%l	Hour (1..12)
%M	Month name (January..December)
%m	Month, numeric (00..12)
%p	AM or PM
%r	Time, 12-hour (hh:mm:ss followed byAM or PM)
%S	Seconds (00..59)
%s	Seconds (00..59)
%T	Time, 24-hour (hh:mm:ss)
%U	Week (00..53), where Sunday is the first day of the week;WEEK() mode 0
%u	Week (00..53), where Monday is the first day of the week;WEEK() mode 1
%V	Week (01..53), where Sunday is the first day of the week;WEEK() mode 2; used with%X
%v	Week (01..53), where Monday is the first day of the week;WEEK() mode 3; used with%x
%W	Weekday name (Sunday..Saturday)
%w	Day of the week (0=Sunday..6=Saturday)
%X	Year for the week where Sunday is the first day of the week, numeric, four digits; used with %V
%x	Year for the week, where Monday is the first day of the week, numeric, four digits; used with %v
%Y	Year, numeric, four digits
%y	Year, numeric (two digits)
%%	A literal % character
%x	x, for any“_x_” not listed above
Ranges for the month and day specifiers begin with zero due to the fact that MySQL permits the storing of incomplete dates such as `'2014-00-00'`.
The language used for day and month names and abbreviations is controlled by the value of thelc_time_names system variable (Section 12.16, “MySQL Server Locale Support”).
For the `%U`, `%u`,`%V`, and `%v` specifiers, see the description of theWEEK() function for information about the mode values. The mode affects how week numbering occurs.
DATE_FORMAT() returns a string with a character set and collation given bycharacter_set_connection andcollation_connection so that it can return month and weekday names containing non-ASCII characters.

mysql> SELECT DATE_FORMAT('2009-10-04 22:23:00', '%W %M %Y');  
        -> 'Sunday October 2009'  
mysql> SELECT DATE_FORMAT('2007-10-04 22:23:00', '%H:%i:%s');  
        -> '22:23:00'  
mysql> SELECT DATE_FORMAT('1900-10-04 22:23:00',  
    ->                 '%D %y %a %d %m %b %j');  
        -> '4th 00 Thu 04 10 Oct 277'  
mysql> SELECT DATE_FORMAT('1997-10-04 22:23:00',  
    ->                 '%H %k %I %r %T %S %w');  
        -> '22 22 10 10:23:00 PM 22:23:00 00 6'  
mysql> SELECT DATE_FORMAT('1999-01-01', '%X %V');  
        -> '1998 52'  
mysql> SELECT DATE_FORMAT('2006-06-00', '%d');  
        -> '00'

DATE_SUB(date,INTERVAL_expr_ unit)
See the description forDATE_ADD().
DAY(date)
DAY() is a synonym forDAYOFMONTH().
DAYNAME(date)
Returns the name of the weekday for_date_. The language used for the name is controlled by the value of thelc_time_names system variable (see Section 12.16, “MySQL Server Locale Support”). ReturnsNULL if date isNULL.

mysql> SELECT DAYNAME('2007-02-03');  
        -> 'Saturday'

DAYOFMONTH(date)
Returns the day of the month for_date, in the range1 to 31, or0 for dates such as'0000-00-00' or'2008-00-00' that have a zero day part. Returns NULL ifdate_ is NULL.

mysql> SELECT DAYOFMONTH('2007-02-03');  
        -> 3

DAYOFWEEK(date)
Returns the weekday index for date (1 = Sunday, 2 = Monday, …, 7 = Saturday). These index values correspond to the ODBC standard. ReturnsNULL if date isNULL.

mysql> SELECT DAYOFWEEK('2007-02-03');  
        -> 7

DAYOFYEAR(date)
Returns the day of the year for_date_, in the range1 to 366. ReturnsNULL if date isNULL.

mysql> SELECT DAYOFYEAR('2007-02-03');  
        -> 34

EXTRACT(unit FROM date)
The EXTRACT() function uses the same kinds of unit specifiers asDATE_ADD() orDATE_SUB(), but extracts parts from the date rather than performing date arithmetic. For information on the unit argument, see Temporal Intervals. ReturnsNULL if date isNULL.

mysql> SELECT EXTRACT(YEAR FROM '2019-07-02');  
        -> 2019  
mysql> SELECT EXTRACT(YEAR_MONTH FROM '2019-07-02 01:02:03');  
        -> 201907  
mysql> SELECT EXTRACT(DAY_MINUTE FROM '2019-07-02 01:02:03');  
        -> 20102  
mysql> SELECT EXTRACT(MICROSECOND  
    ->                FROM '2003-01-02 10:30:00.000123');  
        -> 123

FROM_DAYS(N)
Given a day number N, returns aDATE value. ReturnsNULL if N isNULL.

mysql> SELECT FROM_DAYS(730669);  
        -> '2000-07-03'

Use FROM_DAYS() with caution on old dates. It is not intended for use with values that precede the advent of the Gregorian calendar (1582). SeeSection 13.2.7, “What Calendar Is Used By MySQL?”.

FROM_UNIXTIME(unix_timestamp[,format])
Returns a representation of_unixtimestamp_ as a datetime or character string value. The value returned is expressed using the session time zone. (Clients can set the session time zone as described in Section 7.1.15, “MySQL Server Time Zone Support”.)unixtimestamp is an internal timestamp value representing seconds since'1970-01-01 00:00:00' UTC, such as produced by the UNIX_TIMESTAMP() function.
If format is omitted, this function returns a DATETIME value.
If unixtimestamp or_format_ is NULL, this function returns NULL.
If unixtimestamp is an integer, the fractional seconds precision of theDATETIME is zero. When_unixtimestamp_ is a decimal value, the fractional seconds precision of theDATETIME is the same as the precision of the decimal value, up to a maximum of 6. When_unixtimestamp_ is a floating point number, the fractional seconds precision of the datetime is 6.
On 32-bit platforms, the maximum useful value for_unixtimestamp_ is 2147483647.999999, which returns '2038-01-19 03:14:07.999999' UTC. On 64-bit platforms running MySQL 8.0.28 or later, the effective maximum is 32536771199.999999, which returns '3001-01-18 23:59:59.999999' UTC. Regardless of platform or version, a greater value for_unixtimestamp_ than the effective maximum returns 0.
format is used to format the result in the same way as the format string used for theDATE_FORMAT() function. If_format_ is supplied, the value returned is a VARCHAR.

mysql> SELECT FROM_UNIXTIME(1447430881);  
        -> '2015-11-13 10:08:01'  
mysql> SELECT FROM_UNIXTIME(1447430881) + 0;  
        -> 20151113100801  
mysql> SELECT FROM_UNIXTIME(1447430881,  
    ->                      '%Y %D %M %h:%i:%s %x');  
        -> '2015 13th November 10:08:01 2015'

Note
If you use UNIX_TIMESTAMP() and FROM_UNIXTIME() to convert between values in a non-UTC time zone and Unix timestamp values, the conversion is lossy because the mapping is not one-to-one in both directions. For details, see the description of theUNIX_TIMESTAMP() function.

GET_FORMAT({DATE|TIME|DATETIME}, {'EUR'|'USA'|'JIS'|'ISO'|'INTERNAL'})
Returns a format string. This function is useful in combination with theDATE_FORMAT() and theSTR_TO_DATE() functions.
If format isNULL, this function returnsNULL.
The possible values for the first and second arguments result in several possible format strings (for the specifiers used, see the table in theDATE_FORMAT() function description). ISO format refers to ISO 9075, not ISO 8601.

Function Call	Result
GET_FORMAT(DATE,'USA')	'%m.%d.%Y'
GET_FORMAT(DATE,'JIS')	'%Y-%m-%d'
GET_FORMAT(DATE,'ISO')	'%Y-%m-%d'
GET_FORMAT(DATE,'EUR')	'%d.%m.%Y'
GET_FORMAT(DATE,'INTERNAL')	'%Y%m%d'
GET_FORMAT(DATETIME,'USA')	'%Y-%m-%d %H.%i.%s'
GET_FORMAT(DATETIME,'JIS')	'%Y-%m-%d %H:%i:%s'
GET_FORMAT(DATETIME,'ISO')	'%Y-%m-%d %H:%i:%s'
GET_FORMAT(DATETIME,'EUR')	'%Y-%m-%d %H.%i.%s'
GET_FORMAT(DATETIME,'INTERNAL')	'%Y%m%d%H%i%s'
GET_FORMAT(TIME,'USA')	'%h:%i:%s %p'
GET_FORMAT(TIME,'JIS')	'%H:%i:%s'
GET_FORMAT(TIME,'ISO')	'%H:%i:%s'
GET_FORMAT(TIME,'EUR')	'%H.%i.%s'
GET_FORMAT(TIME,'INTERNAL')	'%H%i%s'
TIMESTAMP can also be used as the first argument toGET_FORMAT(), in which case the function returns the same values as forDATETIME.

mysql> SELECT DATE_FORMAT('2003-10-03',GET_FORMAT(DATE,'EUR'));  
        -> '03.10.2003'  
mysql> SELECT STR_TO_DATE('10.31.2003',GET_FORMAT(DATE,'USA'));  
        -> '2003-10-31'

HOUR(time)
Returns the hour for time. The range of the return value is 0 to23 for time-of-day values. However, the range of TIME values actually is much larger, so HOUR can return values greater than 23. ReturnsNULL if time isNULL.

mysql> SELECT HOUR('10:05:03');  
        -> 10  
mysql> SELECT HOUR('272:59:59');  
        -> 272

LAST_DAY(date)
Takes a date or datetime value and returns the corresponding value for the last day of the month. ReturnsNULL if the argument is invalid orNULL.

mysql> SELECT LAST_DAY('2003-02-05');  
        -> '2003-02-28'  
mysql> SELECT LAST_DAY('2004-02-05');  
        -> '2004-02-29'  
mysql> SELECT LAST_DAY('2004-01-01 01:01:01');  
        -> '2004-01-31'  
mysql> SELECT LAST_DAY('2003-03-32');  
        -> NULL

LOCALTIME,LOCALTIME([fsp])
LOCALTIME andLOCALTIME() are synonyms forNOW().
LOCALTIMESTAMP,LOCALTIMESTAMP([fsp])
LOCALTIMESTAMP andLOCALTIMESTAMP() are synonyms for NOW().
MAKEDATE(year,dayofyear)
Returns a date, given year and day-of-year values.dayofyear must be greater than 0 or the result is NULL. The result is alsoNULL if either argument isNULL.

mysql> SELECT MAKEDATE(2011,31), MAKEDATE(2011,32);  
        -> '2011-01-31', '2011-02-01'  
mysql> SELECT MAKEDATE(2011,365), MAKEDATE(2014,365);  
        -> '2011-12-31', '2014-12-31'  
mysql> SELECT MAKEDATE(2011,0);  
        -> NULL

MAKETIME(hour,minute,second)
Returns a time value calculated from the_hour,minute, andsecond_ arguments. ReturnsNULL if any of its arguments areNULL.
The second argument can have a fractional part.

mysql> SELECT MAKETIME(12,15,30);  
        -> '12:15:30'

MICROSECOND(expr)
Returns the microseconds from the time or datetime expression_expr_ as a number in the range from0 to 999999. ReturnsNULL if expr isNULL.

mysql> SELECT MICROSECOND('12:00:00.123456');  
        -> 123456  
mysql> SELECT MICROSECOND('2019-12-31 23:59:59.000010');  
        -> 10

MINUTE(time)
Returns the minute for time, in the range 0 to 59, orNULL if time isNULL.

mysql> SELECT MINUTE('2008-02-03 10:05:03');  
        -> 5

MONTH(date)
Returns the month for date, in the range 1 to 12 for January to December, or 0 for dates such as'0000-00-00' or'2008-00-00' that have a zero month part. Returns NULL if_date_ is NULL.

mysql> SELECT MONTH('2008-02-03');  
        -> 2

MONTHNAME(date)
Returns the full name of the month for_date_. The language used for the name is controlled by the value of thelc_time_names system variable (Section 12.16, “MySQL Server Locale Support”). ReturnsNULL if date isNULL.

mysql> SELECT MONTHNAME('2008-02-03');  
        -> 'February'

NOW([fsp])
Returns the current date and time as a value in'_`YYYY-MM-DD hh:mm:ss`_' or_YYYYMMDDhhmmss_ format, depending on whether the function is used in string or numeric context. The value is expressed in the session time zone.
If the fsp argument is given to specify a fractional seconds precision from 0 to 6, the return value includes a fractional seconds part of that many digits.

mysql> SELECT NOW();  
        -> '2007-12-15 23:50:26'  
mysql> SELECT NOW() + 0;  
        -> 20071215235026.000000

NOW() returns a constant time that indicates the time at which the statement began to execute. (Within a stored function or trigger,NOW() returns the time at which the function or triggering statement began to execute.) This differs from the behavior forSYSDATE(), which returns the exact time at which it executes.

mysql> SELECT NOW(), SLEEP(2), NOW();  
+---------------------+----------+---------------------+  
| NOW()               | SLEEP(2) | NOW()               |  
+---------------------+----------+---------------------+  
| 2006-04-12 13:47:36 |        0 | 2006-04-12 13:47:36 |  
+---------------------+----------+---------------------+  
mysql> SELECT SYSDATE(), SLEEP(2), SYSDATE();  
+---------------------+----------+---------------------+  
| SYSDATE()           | SLEEP(2) | SYSDATE()           |  
+---------------------+----------+---------------------+  
| 2006-04-12 13:47:44 |        0 | 2006-04-12 13:47:46 |  
+---------------------+----------+---------------------+

In addition, the SET TIMESTAMP statement affects the value returned byNOW() but not bySYSDATE(). This means that timestamp settings in the binary log have no effect on invocations of SYSDATE(). Setting the timestamp to a nonzero value causes each subsequent invocation of NOW() to return that value. Setting the timestamp to zero cancels this effect so that NOW() once again returns the current date and time.
See the description forSYSDATE() for additional information about the differences between the two functions.

PERIOD_ADD(P,N)
Adds N months to period_P_ (in the format_YYMM_ or_YYYYMM). Returns a value in the format YYYYMM.
Note
The period argument P is_not a date value.
This function returns NULL if_P_ or N is NULL.

mysql> SELECT PERIOD_ADD(200801,2);  
        -> 200803

PERIOD_DIFF(P1,P2)
Returns the number of months between periods_P1_ and_P2. P1 and P2 should be in the formatYYMM_ or_YYYYMM. Note that the period arguments P1 andP2_ are not date values.
This function returns NULL if_P1_ or P2 is NULL.

mysql> SELECT PERIOD_DIFF(200802,200703);  
        -> 11

QUARTER(date)
Returns the quarter of the year for_date_, in the range1 to 4, orNULL if date isNULL.

mysql> SELECT QUARTER('2008-04-01');  
        -> 2

SECOND(time)
Returns the second for time, in the range 0 to 59, orNULL if time isNULL.

mysql> SELECT SECOND('10:05:03');  
        -> 3

SEC_TO_TIME(seconds)
Returns the seconds argument, converted to hours, minutes, and seconds, as aTIME value. The range of the result is constrained to that of theTIME data type. A warning occurs if the argument corresponds to a value outside that range.
The function returns NULL if_seconds_ is NULL.

mysql> SELECT SEC_TO_TIME(2378);  
        -> '00:39:38'  
mysql> SELECT SEC_TO_TIME(2378) + 0;  
        -> 3938

STR_TO_DATE(str,format)
This is the inverse of theDATE_FORMAT() function. It takes a string str and a format string format.STR_TO_DATE() returns aDATETIME value if the format string contains both date and time parts, or aDATE orTIME value if the string contains only date or time parts. If_str_ or_format_ is NULL, the function returns NULL. If the date, time, or datetime value extracted from_str_ cannot be parsed according to the rules followed by the server,STR_TO_DATE() returnsNULL and produces a warning.
The server scans str attempting to match format to it. The format string can contain literal characters and format specifiers beginning with %. Literal characters in_format_ must match literally in_str. Format specifiers informat_ must match a date or time part in str. For the specifiers that can be used in format, see theDATE_FORMAT() function description.

mysql> SELECT STR_TO_DATE('01,5,2013','%d,%m,%Y');  
        -> '2013-05-01'  
mysql> SELECT STR_TO_DATE('May 1, 2013','%M %d,%Y');  
        -> '2013-05-01'

Scanning starts at the beginning of_str_ and fails if_format_ is found not to match. Extra characters at the end of str are ignored.

mysql> SELECT STR_TO_DATE('a09:30:17','a%h:%i:%s');  
        -> '09:30:17'  
mysql> SELECT STR_TO_DATE('a09:30:17','%h:%i:%s');  
        -> NULL  
mysql> SELECT STR_TO_DATE('09:30:17a','%h:%i:%s');  
        -> '09:30:17'

Unspecified date or time parts have a value of 0, so incompletely specified values in_str_ produce a result with some or all parts set to 0:

mysql> SELECT STR_TO_DATE('abc','abc');  
        -> '0000-00-00'  
mysql> SELECT STR_TO_DATE('9','%m');  
        -> '0000-09-00'  
mysql> SELECT STR_TO_DATE('9','%s');  
        -> '00:00:09'

Range checking on the parts of date values is as described inSection 13.2.2, “The DATE, DATETIME, and TIMESTAMP Types”. This means, for example, that“zero” dates or dates with part values of 0 are permitted unless the SQL mode is set to disallow such values.

mysql> SELECT STR_TO_DATE('00/00/0000', '%m/%d/%Y');  
        -> '0000-00-00'  
mysql> SELECT STR_TO_DATE('04/31/2004', '%m/%d/%Y');  
        -> '2004-04-31'

If the NO_ZERO_DATE SQL mode is enabled, zero dates are disallowed. In that case,STR_TO_DATE() returnsNULL and generates a warning:

mysql> SET sql_mode = '';  
mysql> SELECT STR_TO_DATE('00/00/0000', '%m/%d/%Y');  
+---------------------------------------+  
| STR_TO_DATE('00/00/0000', '%m/%d/%Y') |  
+---------------------------------------+  
| 0000-00-00                            |  
+---------------------------------------+  
mysql> SET sql_mode = 'NO_ZERO_DATE';  
mysql> SELECT STR_TO_DATE('00/00/0000', '%m/%d/%Y');  
+---------------------------------------+  
| STR_TO_DATE('00/00/0000', '%m/%d/%Y') |  
+---------------------------------------+  
| NULL                                  |  
+---------------------------------------+  
mysql> SHOW WARNINGS\G  
*************************** 1. row ***************************  
  Level: Warning  
   Code: 1411  
Message: Incorrect datetime value: '00/00/0000' for function str_to_date

Prior to MySQL 8.0.35, it was possible to pass an invalid date string such as '2021-11-31' to this function. In MySQL 8.0.35 and later,STR_TO_DATE() performs complete range checking and raises an error if the date after conversion would be invalid.
Note
You cannot use format "%X%V" to convert a year-week string to a date because the combination of a year and week does not uniquely identify a year and month if the week crosses a month boundary. To convert a year-week to a date, you should also specify the weekday:

mysql> SELECT STR_TO_DATE('200442 Monday', '%X%V %W');  
        -> '2004-10-18'

You should also be aware that, for dates and the date portions of datetime values, STR_TO_DATE() checks (only) the individual year, month, and day of month values for validity. More precisely, this means that the year is checked to be sure that it is in the range 0-9999 inclusive, the month is checked to ensure that it is in the range 1-12 inclusive, and the day of month is checked to make sure that it is in the range 1-31 inclusive, but the server does not check the values in combination. For example, SELECT STR_TO_DATE('23-2-31', '%Y-%m-%d') returns2023-02-31. Enabling or disabling theALLOW_INVALID_DATES server SQL mode has no effect on this behavior. SeeSection 13.2.2, “The DATE, DATETIME, and TIMESTAMP Types”, for more information.

SUBDATE(date,INTERVAL_expr_ unit),SUBDATE(expr,days)
When invoked with the INTERVAL form of the second argument, SUBDATE() is a synonym for DATE_SUB(). For information on the INTERVAL unit argument, see the discussion for DATE_ADD().

mysql> SELECT DATE_SUB('2008-01-02', INTERVAL 31 DAY);  
        -> '2007-12-02'  
mysql> SELECT SUBDATE('2008-01-02', INTERVAL 31 DAY);  
        -> '2007-12-02'

The second form enables the use of an integer value for_days_. In such cases, it is interpreted as the number of days to be subtracted from the date or datetime expression expr.

mysql> SELECT SUBDATE('2008-01-02 12:00:00', 31);  
        -> '2007-12-02 12:00:00'

This function returns NULL if any of its arguments are NULL.

SUBTIME(expr1,expr2)
SUBTIME() returns_expr1_ −_expr2_ expressed as a value in the same format as expr1.expr1 is a time or datetime expression, and expr2 is a time expression.
Resolution of this function's return type is performed as it is for the ADDTIME() function; see the description of that function for more information.

mysql> SELECT SUBTIME('2007-12-31 23:59:59.999999','1 1:1:1.000002');  
        -> '2007-12-30 22:58:58.999997'  
mysql> SELECT SUBTIME('01:00:00.999999', '02:00:00.999998');  
        -> '-00:59:59.999999'

This function returns NULL if_expr1_ or_expr2_ is NULL.

SYSDATE([fsp])
Returns the current date and time as a value in'_`YYYY-MM-DD hh:mm:ss`_' or_YYYYMMDDhhmmss_ format, depending on whether the function is used in string or numeric context.
If the fsp argument is given to specify a fractional seconds precision from 0 to 6, the return value includes a fractional seconds part of that many digits.
SYSDATE() returns the time at which it executes. This differs from the behavior forNOW(), which returns a constant time that indicates the time at which the statement began to execute. (Within a stored function or trigger,NOW() returns the time at which the function or triggering statement began to execute.)

mysql> SELECT NOW(), SLEEP(2), NOW();  
+---------------------+----------+---------------------+  
| NOW()               | SLEEP(2) | NOW()               |  
+---------------------+----------+---------------------+  
| 2006-04-12 13:47:36 |        0 | 2006-04-12 13:47:36 |  
+---------------------+----------+---------------------+  
mysql> SELECT SYSDATE(), SLEEP(2), SYSDATE();  
+---------------------+----------+---------------------+  
| SYSDATE()           | SLEEP(2) | SYSDATE()           |  
+---------------------+----------+---------------------+  
| 2006-04-12 13:47:44 |        0 | 2006-04-12 13:47:46 |  
+---------------------+----------+---------------------+

In addition, the SET TIMESTAMP statement affects the value returned byNOW() but not bySYSDATE(). This means that timestamp settings in the binary log have no effect on invocations of SYSDATE().
Because SYSDATE() can return different values even within the same statement, and is not affected by SET TIMESTAMP, it is nondeterministic and therefore unsafe for replication if statement-based binary logging is used. If that is a problem, you can use row-based logging.
Alternatively, you can use the--sysdate-is-now option to cause SYSDATE() to be an alias for NOW(). This works if the option is used on both the replication source server and the replica.
The nondeterministic nature ofSYSDATE() also means that indexes cannot be used for evaluating expressions that refer to it.

TIME(expr)
Extracts the time part of the time or datetime expression_expr_ and returns it as a string. Returns NULL if_expr_ is NULL.
This function is unsafe for statement-based replication. A warning is logged if you use this function whenbinlog_format is set toSTATEMENT.

mysql> SELECT TIME('2003-12-31 01:02:03');  
        -> '01:02:03'  
mysql> SELECT TIME('2003-12-31 01:02:03.000123');  
        -> '01:02:03.000123'

TIMEDIFF(expr1,expr2)
TIMEDIFF() returns_expr1_ −_expr2_ expressed as a time value.expr1 and_expr2_ are strings which are converted to TIME orDATETIME expressions; these must be of the same type following conversion. ReturnsNULL if expr1 or_expr2_ is NULL.
The result returned by TIMEDIFF() is limited to the range allowed forTIME values. Alternatively, you can use either of the functionsTIMESTAMPDIFF() andUNIX_TIMESTAMP(), both of which return integers.

mysql> SELECT TIMEDIFF('2000-01-01 00:00:00',  
    ->                 '2000-01-01 00:00:00.000001');  
        -> '-00:00:00.000001'  
mysql> SELECT TIMEDIFF('2008-12-31 23:59:59.000001',  
    ->                 '2008-12-30 01:01:01.000002');  
        -> '46:58:57.999999'

TIMESTAMP(expr),TIMESTAMP(expr1,expr2)
With a single argument, this function returns the date or datetime expression expr as a datetime value. With two arguments, it adds the time expression expr2 to the date or datetime expression expr1 and returns the result as a datetime value. ReturnsNULL if expr,expr1, or_expr2_ is NULL.

mysql> SELECT TIMESTAMP('2003-12-31');  
        -> '2003-12-31 00:00:00'  
mysql> SELECT TIMESTAMP('2003-12-31 12:00:00','12:00:00');  
        -> '2004-01-01 00:00:00'

TIMESTAMPADD(unit,interval,datetime_expr)
Adds the integer expression_interval_ to the date or datetime expression datetimeexpr. The unit for interval is given by the_unit_ argument, which should be one of the following values: MICROSECOND (microseconds), SECOND,MINUTE, HOUR,DAY, WEEK,MONTH, QUARTER, orYEAR.
The unit value may be specified using one of keywords as shown, or with a prefix ofSQL_TSI_. For example,DAY and SQL_TSI_DAY both are legal.
This function returns NULL if_interval_ or_datetimeexpr_ isNULL.

mysql> SELECT TIMESTAMPADD(MINUTE, 1, '2003-01-02');  
        -> '2003-01-02 00:01:00'  
mysql> SELECT TIMESTAMPADD(WEEK,1,'2003-01-02');  
        -> '2003-01-09'

mysql> SELECT TIMESTAMPADD(MONTH, 1, DATE '2024-03-30') AS t1,  
     >        TIMESTAMPADD(MONTH, 1, DATE '2024-03-31') AS t2;  
+------------+------------+  
| t1         | t2         |  
+------------+------------+  
| 2024-04-30 | 2024-04-30 |  
+------------+------------+  
1 row in set (0.00 sec)

TIMESTAMPDIFF(unit,datetime_expr1,datetime_expr2)
Returns datetimeexpr2 −_datetimeexpr1, wheredatetimeexpr1_ and_datetimeexpr2_ are date or datetime expressions. One expression may be a date and the other a datetime; a date value is treated as a datetime having the time part '00:00:00' where necessary. The unit for the result (an integer) is given by the_unit_ argument. The legal values for_unit_ are the same as those listed in the description of theTIMESTAMPADD() function.
This function returns NULL if_datetimeexpr1_ or_datetimeexpr2_ isNULL.

mysql> SELECT TIMESTAMPDIFF(MONTH,'2003-02-01','2003-05-01');  
        -> 3  
mysql> SELECT TIMESTAMPDIFF(YEAR,'2002-05-01','2001-01-01');  
        -> -1  
mysql> SELECT TIMESTAMPDIFF(MINUTE,'2003-02-01','2003-05-01 12:05:55');  
        -> 128885

Note
The order of the date or datetime arguments for this function is the opposite of that used with theTIMESTAMP() function when invoked with 2 arguments.

TIME_FORMAT(time,format)
This is used like theDATE_FORMAT() function, but the_format_ string may contain format specifiers only for hours, minutes, seconds, and microseconds. Other specifiers produce a NULL or0. TIME_FORMAT() returnsNULL if time or_format_ is NULL.
If the time value contains an hour part that is greater than 23, the%H and %k hour format specifiers produce a value larger than the usual range of0..23. The other hour format specifiers produce the hour value modulo 12.

mysql> SELECT TIME_FORMAT('100:00:00', '%H %k %h %I %l');  
        -> '100 100 04 04 4'

TIME_TO_SEC(time)
Returns the time argument, converted to seconds. Returns NULL if_time_ is NULL.

mysql> SELECT TIME_TO_SEC('22:23:00');  
        -> 80580  
mysql> SELECT TIME_TO_SEC('00:39:38');  
        -> 2378

TO_DAYS(date)
Given a date date, returns a day number (the number of days since year 0). ReturnsNULL if date isNULL.

mysql> SELECT TO_DAYS(950501);  
        -> 728779  
mysql> SELECT TO_DAYS('2007-10-07');  
        -> 733321

TO_DAYS() is not intended for use with values that precede the advent of the Gregorian calendar (1582), because it does not take into account the days that were lost when the calendar was changed. For dates before 1582 (and possibly a later year in other locales), results from this function are not reliable. SeeSection 13.2.7, “What Calendar Is Used By MySQL?”, for details.
Remember that MySQL converts two-digit year values in dates to four-digit form using the rules inSection 13.2, “Date and Time Data Types”. For example,'2008-10-07' and'08-10-07' are seen as identical dates:

mysql> SELECT TO_DAYS('2008-10-07'), TO_DAYS('08-10-07');  
        -> 733687, 733687

In MySQL, the zero date is defined as'0000-00-00', even though this date is itself considered invalid. This means that, for'0000-00-00' and'0000-01-01',TO_DAYS() returns the values shown here:

mysql> SELECT TO_DAYS('0000-00-00');  
+-----------------------+  
| to_days('0000-00-00') |  
+-----------------------+  
|                  NULL |  
+-----------------------+  
1 row in set, 1 warning (0.00 sec)  
mysql> SHOW WARNINGS;  
+---------+------+----------------------------------------+  
| Level   | Code | Message                                |  
+---------+------+----------------------------------------+  
| Warning | 1292 | Incorrect datetime value: '0000-00-00' |  
+---------+------+----------------------------------------+  
1 row in set (0.00 sec)  
mysql> SELECT TO_DAYS('0000-01-01');  
+-----------------------+  
| to_days('0000-01-01') |  
+-----------------------+  
|                     1 |  
+-----------------------+  
1 row in set (0.00 sec)

This is true whether or not theALLOW_INVALID_DATES SQL server mode is enabled.

TO_SECONDS(expr)
Given a date or datetime expr, returns the number of seconds since the year 0. If_expr_ is not a valid date or datetime value (including NULL), it returnsNULL.

mysql> SELECT TO_SECONDS(950501);  
        -> 62966505600  
mysql> SELECT TO_SECONDS('2009-11-29');  
        -> 63426672000  
mysql> SELECT TO_SECONDS('2009-11-29 13:43:32');  
        -> 63426721412  
mysql> SELECT TO_SECONDS( NOW() );  
        -> 63426721458

Like TO_DAYS(),TO_SECONDS() is not intended for use with values that precede the advent of the Gregorian calendar (1582), because it does not take into account the days that were lost when the calendar was changed. For dates before 1582 (and possibly a later year in other locales), results from this function are not reliable. SeeSection 13.2.7, “What Calendar Is Used By MySQL?”, for details.
Like TO_DAYS(),TO_SECONDS(), converts two-digit year values in dates to four-digit form using the rules inSection 13.2, “Date and Time Data Types”.
In MySQL, the zero date is defined as'0000-00-00', even though this date is itself considered invalid. This means that, for'0000-00-00' and'0000-01-01',TO_SECONDS() returns the values shown here:

mysql> SELECT TO_SECONDS('0000-00-00');  
+--------------------------+  
| TO_SECONDS('0000-00-00') |  
+--------------------------+  
|                     NULL |  
+--------------------------+  
1 row in set, 1 warning (0.00 sec)  
mysql> SHOW WARNINGS;  
+---------+------+----------------------------------------+  
| Level   | Code | Message                                |  
+---------+------+----------------------------------------+  
| Warning | 1292 | Incorrect datetime value: '0000-00-00' |  
+---------+------+----------------------------------------+  
1 row in set (0.00 sec)  
mysql> SELECT TO_SECONDS('0000-01-01');  
+--------------------------+  
| TO_SECONDS('0000-01-01') |  
+--------------------------+  
|                    86400 |  
+--------------------------+  
1 row in set (0.00 sec)

This is true whether or not theALLOW_INVALID_DATES SQL server mode is enabled.

UNIX_TIMESTAMP([date])
If UNIX_TIMESTAMP() is called with no date argument, it returns a Unix timestamp representing seconds since '1970-01-01 00:00:00' UTC.
If UNIX_TIMESTAMP() is called with a date argument, it returns the value of the argument as seconds since'1970-01-01 00:00:00' UTC. The server interprets date as a value in the session time zone and converts it to an internal Unix timestamp value in UTC. (Clients can set the session time zone as described in Section 7.1.15, “MySQL Server Time Zone Support”.) The_date_ argument may be aDATE,DATETIME, orTIMESTAMP string, or a number in YYMMDD,YYMMDDhhmmss,YYYYMMDD, or_YYYYMMDDhhmmss_ format. If the argument includes a time part, it may optionally include a fractional seconds part.
The return value is an integer if no argument is given or the argument does not include a fractional seconds part, orDECIMAL if an argument is given that includes a fractional seconds part.
When the date argument is aTIMESTAMP column,UNIX_TIMESTAMP() returns the internal timestamp value directly, with no implicit“string-to-Unix-timestamp” conversion.
Prior to MySQL 8.0.28, the valid range of argument values is the same as for the TIMESTAMP data type: '1970-01-01 00:00:01.000000' UTC to '2038-01-19 03:14:07.999999' UTC. This is also the case in MySQL 8.0.28 and later for 32-bit platforms. For MySQL 8.0.28 and later running on 64-bit platforms, the valid range of argument values forUNIX_TIMESTAMP() is '1970-01-01 00:00:01.000000' UTC to '3001-01-19 03:14:07.999999' UTC (corresponding to 32536771199.999999 seconds).
Regardless of MySQL version or platform architecture, if you pass an out-of-range date toUNIX_TIMESTAMP(), it returns0. If date isNULL, it returns NULL.

mysql> SELECT UNIX_TIMESTAMP();  
        -> 1447431666  
mysql> SELECT UNIX_TIMESTAMP('2015-11-13 10:20:19');  
        -> 1447431619  
mysql> SELECT UNIX_TIMESTAMP('2015-11-13 10:20:19.012');  
        -> 1447431619.012

If you use UNIX_TIMESTAMP() andFROM_UNIXTIME() to convert between values in a non-UTC time zone and Unix timestamp values, the conversion is lossy because the mapping is not one-to-one in both directions. For example, due to conventions for local time zone changes such as Daylight Saving Time (DST), it is possible forUNIX_TIMESTAMP() to map two values that are distinct in a non-UTC time zone to the same Unix timestamp value.FROM_UNIXTIME() maps that value back to only one of the original values. Here is an example, using values that are distinct in the MET time zone:

mysql> SET time_zone = 'MET';  
mysql> SELECT UNIX_TIMESTAMP('2005-03-27 03:00:00');  
+---------------------------------------+  
| UNIX_TIMESTAMP('2005-03-27 03:00:00') |  
+---------------------------------------+  
|                            1111885200 |  
+---------------------------------------+  
mysql> SELECT UNIX_TIMESTAMP('2005-03-27 02:00:00');  
+---------------------------------------+  
| UNIX_TIMESTAMP('2005-03-27 02:00:00') |  
+---------------------------------------+  
|                            1111885200 |  
+---------------------------------------+  
mysql> SELECT FROM_UNIXTIME(1111885200);  
+---------------------------+  
| FROM_UNIXTIME(1111885200) |  
+---------------------------+  
| 2005-03-27 03:00:00       |  
+---------------------------+

If you want to subtractUNIX_TIMESTAMP() columns, you might want to cast them to signed integers. SeeSection 14.10, “Cast Functions and Operators”.

UTC_DATE,UTC_DATE()
Returns the current UTC date as a value in'_`YYYY-MM-DD`_' or_YYYYMMDD_ format, depending on whether the function is used in string or numeric context.

mysql> SELECT UTC_DATE(), UTC_DATE() + 0;  
        -> '2003-08-14', 20030814

UTC_TIME,UTC_TIME([fsp])
Returns the current UTC time as a value in_'hh:mm:ss'_ or_hhmmss_ format, depending on whether the function is used in string or numeric context.
If the fsp argument is given to specify a fractional seconds precision from 0 to 6, the return value includes a fractional seconds part of that many digits.

mysql> SELECT UTC_TIME(), UTC_TIME() + 0;  
        -> '18:07:53', 180753.000000

UTC_TIMESTAMP,UTC_TIMESTAMP([fsp])
Returns the current UTC date and time as a value in'_`YYYY-MM-DD hh:mm:ss`_' or_YYYYMMDDhhmmss_ format, depending on whether the function is used in string or numeric context.
If the fsp argument is given to specify a fractional seconds precision from 0 to 6, the return value includes a fractional seconds part of that many digits.

mysql> SELECT UTC_TIMESTAMP(), UTC_TIMESTAMP() + 0;  
        -> '2003-08-14 18:08:04', 20030814180804.000000

WEEK(date[,mode])
This function returns the week number for_date. The two-argument form ofWEEK() enables you to specify whether the week starts on Sunday or Monday and whether the return value should be in the range from 0 to 53 or from 1 to53. If the mode argument is omitted, the value of thedefault_week_format system variable is used. SeeSection 7.1.8, “Server System Variables”. For aNULL date value, the function returnsNULL.
The following table describes how themode_ argument works.

Mode	First day of week	Range	Week 1 is the first week …
0	Sunday	0-53	with a Sunday in this year
1	Monday	0-53	with 4 or more days this year
2	Sunday	1-53	with a Sunday in this year
3	Monday	1-53	with 4 or more days this year
4	Sunday	0-53	with 4 or more days this year
5	Monday	0-53	with a Monday in this year
6	Sunday	1-53	with 4 or more days this year
7	Monday	1-53	with a Monday in this year
For `mode` values with a meaning of“with 4 or more days this year,” weeks are numbered according to ISO 8601:1988:

If the week containing January 1 has 4 or more days in the new year, it is week 1.
Otherwise, it is the last week of the previous year, and the next week is week 1.

mysql> SELECT WEEK('2008-02-20');  
        -> 7  
mysql> SELECT WEEK('2008-02-20',0);  
        -> 7  
mysql> SELECT WEEK('2008-02-20',1);  
        -> 8  
mysql> SELECT WEEK('2008-12-31',1);  
        -> 53

If a date falls in the last week of the previous year, MySQL returns 0 if you do not use2, 3,6, or 7 as the optional_mode_ argument:

mysql> SELECT YEAR('2000-01-01'), WEEK('2000-01-01',0);  
        -> 2000, 0

One might argue that WEEK() should return 52 because the given date actually occurs in the 52nd week of 1999.WEEK() returns0 instead so that the return value is“the week number in the given year.” This makes use of the WEEK() function reliable when combined with other functions that extract a date part from a date.
If you prefer a result evaluated with respect to the year that contains the first day of the week for the given date, use0, 2,5, or 7 as the optional_mode_ argument.

mysql> SELECT WEEK('2000-01-01',2);  
        -> 52

Alternatively, use theYEARWEEK() function:

mysql> SELECT YEARWEEK('2000-01-01');  
        -> 199952  
mysql> SELECT MID(YEARWEEK('2000-01-01'),5,2);  
        -> '52'

WEEKDAY(date)
Returns the weekday index for date (0 = Monday, 1 = Tuesday, … 6 = Sunday). ReturnsNULL if date isNULL.

mysql> SELECT WEEKDAY('2008-02-03 22:23:00');  
        -> 6  
mysql> SELECT WEEKDAY('2007-11-06');  
        -> 1

WEEKOFYEAR(date)
Returns the calendar week of the date as a number in the range from 1 to 53. ReturnsNULL if date isNULL.
WEEKOFYEAR() is a compatibility function that is equivalent toWEEK(date,3).

mysql> SELECT WEEKOFYEAR('2008-02-20');  
        -> 8

YEAR(date)
Returns the year for date, in the range 1000 to 9999, or0 for the “zero” date. ReturnsNULL if date isNULL.

mysql> SELECT YEAR('1987-01-01');  
        -> 1987

YEARWEEK(date),YEARWEEK(date,mode)
Returns year and week for a date. The year in the result may be different from the year in the date argument for the first and the last week of the year. Returns NULL if date is NULL.
The mode argument works exactly like the mode argument toWEEK(). For the single-argument syntax, a mode value of 0 is used. Unlike WEEK(), the value ofdefault_week_format does not influence YEARWEEK().

mysql> SELECT YEARWEEK('1987-01-01');  
        -> 198652

The week number is different from what theWEEK() function would return (0) for optional arguments0 or 1, asWEEK() then returns the week in the context of the given year.