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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)
Updated on: 10-Dec-2019
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