Oracle NULLIF Function

The Oracle NULLIF function syntax of the Oracle NULLIF function is NULLIF (expression 1, expression 2). If expression 1 and expression 2 are equal, a null value is returned, if expression 1 and expression 2 are not equal, the result of expression 1 is returned. Note: expression 1 and expression 2 should be of the same data type or can be implicitly converted to the same data type. Expression 1 cannot use the character null. Example 1 of www.2cto.com: If sal is 888, a blank [SQL] SQL> select. ename,. sal, nullif (sal, 8888) value from emp; ename sal value ------------------ ---------- SMITH 99 ALLEN 8888 WARD 8888 JONES 8888 MARTIN 8888 BLAKE 8888 CLARK 8888 SCOTT 999 999 KING 8888 TURNER 8888 ADAMS 8888 JAMES 8888 FORD 8888 MILLER 8888 xiangyc 9999.88 9999.88 already select 15 rows. At www.2cto.com, we can see that equal is null. If not, expression 1 is returned. Example 2: [SQL] SQL> select nullif (3 + 5, 8) value from dual; VALUE ---------- Example 3: it is proved that the first expression cannot use the character null [SQL] SQL> select nullif (null, 8) value from dual; select nullif (null, 8) value from dual * 1st line with an error: ORA-00932: Data Type inconsistent: Should be-, but get CHAR