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How can we check for NULL in a MySQL query?
With the help of IS NULL operator, we can check for NULL in a MySQL query. We cannot use = (comparison operator) because as we know that NULL is not a value. Following example using the data from ‘employee’ table will exhibit it −
Example
mysql> Select * from Employee WHERE Salary IS NULL; +----+-------+--------+ | ID | Name | Salary | +----+-------+--------+ | 7 | Aryan | NULL | | 8 | Vinay | NULL | +----+-------+--------+ 2 rows in set (0.00 sec)
The query above use IS NULL operator and produces the output where salary column is having NULL.
mysql> Select * from employee where salary = NULL; Empty set (0.00 sec)
The query above use = (Comparison operator) hence produces the empty set because with NULL is not a value.
Updated on: 20-Jun-2020
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