NULLIF
nullifβ
descriptionβ
Syntaxβ
nullif(expr1, expr2)
If the two parameters are equal, null is returned. Otherwise, the value of the first parameter is returned. It has the same effect as the following case when
CASE
WHEN expr1 = expr2 THEN NULL
ELSE expr1
END
exampleβ
mysql> select nullif(1,1);
+--------------+
| nullif(1, 1) |
+--------------+
| NULL |
+--------------+
mysql> select nullif(1,0);
+--------------+
| nullif(1, 0) |
+--------------+
| 1 |
+--------------+
keywordsβ
NULLIF