Mysql OPERATOR EQUAL TO
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MySQL NULL-Safe Equal <=>
This operator performs an equality comparison like the = operator, but returns 1 rather than NULL if both operands are NULL, and 0 rather than NULL if one operand is NULL.
Syntax
N1 <=> N2;
Example 1
mysql> SELECT 3 <=> 3, NULL <=> NULL, 3 <=> NULL; +---------+---------------+------------+ | 3 <=> 3 | NULL <=> NULL | 3 <=> NULL | +---------+---------------+------------+ | 1 | 1 | 0 | +---------+---------------+------------+ 1 row in set (0.00 sec)
Example 2
mysql> SELECT 3 <=> 3, 3 = 3, NULL <=> 3, NULL = 3; +---------+-------+------------+----------+ | 3 <=> 3 | 3 = 3 | NULL <=> 3 | NULL = 3 | +---------+-------+------------+----------+ | 1 | 1 | 0 | NULL | +---------+-------+------------+----------+ 1 row in set (0.00 sec)
Related Links
- BETWEEN ... AND ...
- COALESCE
- <=>
- =
- >=
- >
