Perform MySQL SELECT on fields containing null values?

To check for NULL values in SELECT, use MySQL NULL. Let us first create a table −

mysql> create table DemoTable1455    -> (    -> Name varchar(20)    -> ); Query OK, 0 rows affected (0.47 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1455 values('John'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable1455 values(NULL); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1455 values(''); Query OK, 1 row affected (0.19 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1455;

This will produce the following output −

+------+ | Name | +------+ | John | | NULL | |      | +------+ 3 rows in set (0.00 sec)

Following is the query to perform MySQL select on fields containing null values −

mysql> select * from DemoTable1455 where Name <> 'John' or Name is null;

This will produce the following output −

+------+ | Name | +------+ | NULL | |      | +------+ 2 rows in set (0.00 sec)