NULLIF
Descriptionβ
Returns NULL
if the two input values are equal; otherwise, returns the first input value. This function is equivalent to the following CASE WHEN
expression:
CASE
WHEN <expr1> = <expr2> THEN NULL
ELSE <expr1>
END
Syntaxβ
NULLIF(<expr1>, <expr2>)
Parametersβ
Parameter | Description |
---|---|
<expr1> | The first input value to compare. |
<expr2> | The second input value to compare against the first. |
Return Valueβ
- Returns
NULL
if<expr1>
is equal to<expr2>
. - Otherwise, returns the value of
<expr1>
.
Examplesβ
SELECT NULLIF(1, 1);
+--------------+
| NULLIF(1, 1) |
+--------------+
| NULL |
+--------------+
SELECT NULLIF(1, 0);
+--------------+
| NULLIF(1, 0) |
+--------------+
| 1 |
+--------------+