String Functions and Operators (original) (raw)

ascii(string)

int

ASCII code of the first character of the argument. For UTF8 returns the Unicode code point of the character. For other multibyte encodings, the argument must be anASCII character.

ascii('x')

120

btrim(string text [, characters text])

text

Remove the longest string consisting only of characters incharacters (a space by default) from the start and end of string

btrim('xyxtrimyyx', 'xyz')

trim

chr(int)

text

Character with the given code. For UTF8 the argument is treated as a Unicode code point. For other multibyte encodings the argument must designate anASCII character. The NULL (0) character is not allowed because text data types cannot store such bytes.

chr(65)

concat(str "any" [, str "any" [, ...] ])

text

Concatenate the text representations of all the arguments. NULL arguments are ignored.

concat('abcde', 2, NULL, 22)

abcde222

concat_ws(sep text, str "any" [, str "any" [, ...] ])

text

Concatenate all but the first argument with separators. The first argument is used as the separator string. NULL arguments are ignored.

concat_ws(',', 'abcde', 2, NULL, 22)

abcde,2,22

convert(string bytea, src_encoding name,dest_encoding name)

bytea

Convert string to dest_encoding. The original encoding is specified by src_encoding. The string must be valid in this encoding. Conversions can be defined by CREATE CONVERSION. Also there are some predefined conversions. See Table 9-8 for available conversions.

convert('text_in_utf8', 'UTF8', 'LATIN1')

text_in_utf8 represented in Latin-1 encoding (ISO 8859-1)

convert_from(string bytea, src_encoding name)

text

Convert string to the database encoding. The original encoding is specified by src_encoding. Thestring must be valid in this encoding.

convert_from('text_in_utf8', 'UTF8')

text_in_utf8 represented in the current database encoding

convert_to(string text, dest_encoding name)

bytea

Convert string to dest_encoding.

convert_to('some text', 'UTF8')

some text represented in the UTF8 encoding

decode(string text, format text)

bytea

Decode binary data from textual representation in string. Options for format are same as in encode.

decode('MTIzAAE=', 'base64')

\x3132330001

encode(data bytea, format text)

text

Encode binary data into a textual representation. Supported formats are: base64, hex, escape. escape converts zero bytes and high-bit-set bytes to octal sequences (\nnn) and doubles backslashes.

encode('123\000\001', 'base64')

MTIzAAE=

format(formatstr text [, formatarg "any" [, ...] ])

text

Format arguments according to a format string. This function is similar to the C function sprintf. See Section 9.4.1.

format('Hello %s, %1$s', 'World')

Hello World, World

initcap(string)

text

Convert the first letter of each word to upper case and the rest to lower case. Words are sequences of alphanumeric characters separated by non-alphanumeric characters.

initcap('hi THOMAS')

Hi Thomas

left(str text, n int)

text

Return first n characters in the string. When n is negative, return all but last |n| characters.

left('abcde', 2)

length(string)

int

Number of characters in string

length('jose')

length(string bytea, encoding name)

int

Number of characters in string in the given encoding. The string must be valid in this encoding.

length('jose', 'UTF8')

lpad(string text, length int [, fill text])

text

Fill up the string to lengthlength by prepending the charactersfill (a space by default). If thestring is already longer than length then it is truncated (on the right).

lpad('hi', 5, 'xy')

xyxhi

ltrim(string text [, characters text])

text

Remove the longest string containing only characters fromcharacters (a space by default) from the start of string

ltrim('zzzytest', 'xyz')

test

md5(string)

text

Calculates the MD5 hash of string, returning the result in hexadecimal

md5('abc')

900150983cd24fb0 d6963f7d28e17f72

pg_client_encoding()

name

Current client encoding name

pg_client_encoding()

SQL_ASCII

quote_ident(string text)

text

Return the given string suitably quoted to be used as an identifier in an SQL statement string. Quotes are added only if necessary (i.e., if the string contains non-identifier characters or would be case-folded). Embedded quotes are properly doubled. See also Example 40-1.

quote_ident('Foo bar')

"Foo bar"

quote_literal(string text)

text

Return the given string suitably quoted to be used as a string literal in an SQL statement string. Embedded single-quotes and backslashes are properly doubled. Note that quote_literalreturns null on null input; if the argument might be null,quote_nullable is often more suitable. See also Example 40-1.

quote_literal(E'O\'Reilly')

'O''Reilly'

quote_literal(value anyelement)

text

Coerce the given value to text and then quote it as a literal. Embedded single-quotes and backslashes are properly doubled.

quote_literal(42.5)

'42.5'

quote_nullable(string text)

text

Return the given string suitably quoted to be used as a string literal in an SQL statement string; or, if the argument is null, return NULL. Embedded single-quotes and backslashes are properly doubled. See also Example 40-1.

quote_nullable(NULL)

NULL

quote_nullable(value anyelement)

text

Coerce the given value to text and then quote it as a literal; or, if the argument is null, return NULL. Embedded single-quotes and backslashes are properly doubled.

quote_nullable(42.5)

'42.5'

regexp_matches(string text, pattern text [, flags text])

setof text[]

Return all captured substrings resulting from matching a POSIX regular expression against the string. See Section 9.7.3for more information.

regexp_matches('foobarbequebaz', '(bar)(beque)')

{bar,beque}

regexp_replace(string text, pattern text, replacement text [, flags text])

text

Replace substring(s) matching a POSIX regular expression. SeeSection 9.7.3 for more information.

regexp_replace('Thomas', '.[mN]a.', 'M')

ThM

regexp_split_to_array(string text, pattern text [, flags text ])

text[]

Split string using a POSIX regular expression as the delimiter. See Section 9.7.3for more information.

regexp_split_to_array('hello world', '\s+')

{hello,world}

regexp_split_to_table(string text, pattern text [, flags text])

setof text

Split string using a POSIX regular expression as the delimiter. See Section 9.7.3for more information.

regexp_split_to_table('hello world', '\s+')

hello

world

(2 rows)

repeat(string text, number int)

text

Repeat string the specifiednumber of times

repeat('Pg', 4)

PgPgPgPg

replace(string text, from text, to text)

text

Replace all occurrences in string of substring from with substring to

replace('abcdefabcdef', 'cd', 'XX')

abXXefabXXef

reverse(str)

text

Return reversed string.

reverse('abcde')

edcba

right(str text, n int)

text

Return last n characters in the string. When n is negative, return all but first |n| characters.

right('abcde', 2)

rpad(string text, length int [, fill text])

text

Fill up the string to lengthlength by appending the charactersfill (a space by default). If thestring is already longer than length then it is truncated.

rpad('hi', 5, 'xy')

hixyx

rtrim(string text [, characters text])

text

Remove the longest string containing only characters fromcharacters (a space by default) from the end of string

rtrim('testxxzx', 'xyz')

test

split_part(string text, delimiter text, field int)

text

Split string on delimiter and return the given field (counting from one)

split_part('abc~@~def~@~ghi', '~@~', 2)

def

strpos(string, substring)

int

Location of specified substring (same as position(substring instring), but note the reversed argument order)

strpos('high', 'ig')

substr(string, from[, count])

text

Extract substring (same as substring(string fromfrom for count))

substr('alphabet', 3, 2)

to_ascii(string text [, encoding text])

text

Convert string to ASCII from another encoding (only supports conversion from LATIN1, LATIN2, LATIN9, andWIN1250 encodings)

to_ascii('Karel')

Karel

to_hex(number int or bigint)

text

Convert number to its equivalent hexadecimal representation

to_hex(2147483647)

7fffffff

translate(string text, from text, to text)

text

Any character in string that matches a character in the from set is replaced by the corresponding character in the toset. If from is longer than to, occurrences of the extra characters infrom are removed.

translate('12345', '143', 'ax')

a2x5