Python MySQL Insert record if not exists in table (original) (raw)

Last Updated : 13 Nov, 2023

In this article, we will try to insert records and check if they **EXISTS or not. The EXISTS condition in SQL is used to check if the result of a correlated nested query is empty (contains no tuples) or not. It can be used to **INSERT, **SELECT, **UPDATE, or **DELETE statements.

**Pre-requisite

• Connect MySQL Database to Python
• Python

Insert Record If Not Exists in Table

**Query Used:

INSERT INTO table-name(col1, col2, col3) \
SELECT * FROM (SELECT val1, val2, val3) as temp \    
WHERE NOT EXISTS \    
(SELECT primary-key FROM table-name WHERE primary-key = inserted-record) LIMIT 1

Suppose we have a database called _test and a table named _geeksfoegeeks. Below are the schema and data of the table:

Database

Since each individual has a unique identification number, we will insert records and check the _ID_NO of that person. If _ID_NO is not already present in the table, the record will be inserted, else the record will be discarded.

Inserting Record When the Record Does Not Exists

In this example, we are inserting the record when the record already exists. We know that each individual has a unique identification number, then we will insert records and check the ID_NO of that person and if ID_NO is not already present in the table then the record will be inserted.

Python3

import pymysql

connection = pymysql.connect(

`` host = "localhost" ,

`` user = "root" ,

`` password = "1234" ,

`` port = 3306 ,

`` db = "test"

)

mycursor = connection.cursor()

mycursor.execute( "Select * from geeksfoegeeks" )

myresult = mycursor.fetchall()

for i in myresult:

`` print (i)

mycursor.execute(

`` "Insert into geeksfoegeeks(name,address,age,mob_number,ID_NO) \

`` select * from ( Select 'Thomas' , 'UK' , 30 , 1892345670 , 'IND100' ) as temp \

`` where not exists \

`` (Select ID_NO from geeksfoegeeks where ID_NO = 'IND100' ) LIMIT 1 ")

print ( "After inserting a record...." )

mycursor.execute( "Select * from geeksfoegeeks" )

myresult = mycursor.fetchall()

for i in myresult:

`` print (i)

mycursor.execute( "Commit" )

connection.close()

**Output

Python Output after insertion

In the above, output we could see that the record _(‘Thomas’,’UK’,30,1892345670,’IND100′) was inserted into MySQL table.

Insert Record When The Record Exists

Below are the schema and data of the table _geeksdemo in database geek:

In this example, we will try to insert the record when the record already exists. We know that each individual has a unique identification number, then we will insert records and check the ID_NO of that person and if ID_NO is present in the table then the record will be discarded.

Python3

import pymysql

connection = pymysql.connect(

`` host = "localhost" ,

`` user = "root" ,

`` password = "",

`` port = 3306 ,

`` db = "geek"

)

mycursor = connection.cursor()

mycursor.execute( "Select * from geeksdemo" )

myresult = mycursor.fetchall()

for i in myresult:

`` print (i)

mycursor.execute(

`` "Insert into geeksdemo( id ,name,gender,dept) \

`` select * from ( Select 5 , 'Thomas' , 'm' , 'information technology' ) as temp \

`` where not exists \

`` (Select id from geeksdemo where id = 5 ) LIMIT 1 ")

print ( "After inserting a record...." )

mycursor.execute( "Select * from geeksdemo" )

myresult = mycursor.fetchall()

for i in myresult:

`` print (i)

mycursor.execute( "Commit" )

connection.close()

**Output

We observe that record _(5,’Thomas’,’m’,’information technology’) was not inserted into the table again. The following image is the output of MySQL database, after running the above python script.

We can see that 0 rows were affected. Therefore, no record was inserted as it already existed in the table with another record.