In Oracle/PLSQL, the NULLIF function compares expr1 and expr2. If expr1 and expr2 are equal, the NULLIF function returns NULL. Otherwise, it returns expr1.
Syntax
The syntax for the NULLIF function is:
NULLIF( expr1, expr2 )
expr1 and expr2 must be either numeric values or values that are of the same datatype.
Note
expr1 can be an expression that evaluates to NULL, but it can not be the literal NULL.
Applies To
For Example
| NULLIF(12, 12) | would return NULL |
| NULLIF(12, 13) | would return 12 |
| NULLIF('apples', 'apples') | would return NULL |
| NULLIF('apples', 'oranges') | would return 'apples' |
| NULLIF(NULL, 12) | would return an ORA-00932 error because |