Oracle PL/SQL/Conversion Functions/NULLIF

NULLIF() compares two expressions. If they are equal, it returns NULL. Otherwise, it returns the first expression.

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SQL> Syntax: NULLIF( <expression1>,<expression2>) SQL> SQL> SELECT

 2     NULLIF("ABC","ABC")  equal,
 3     NULLIF ("ABC","DEF") diff from dual;

EQU DIF --- ---

   ABC
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select nullif( 1, 1 )

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SQL> SQL> select nullif( 1, 1 )

 2  from dual;

NULLIF(1,1)

---

1 row selected. SQL> SQL> --

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select nullif( 1, null )

   <source lang="sql">

SQL> SQL> select nullif( 1, null )

 2  from dual;

NULLIF(1,NULL)

---

            1

1 row selected. SQL> SQL> SQL> --

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