NVL2函数

文档地址：http://docs.oracle.com/cd/B19306_01/server.102/b14200/functions106.htm#SQLRF00685

 

NVL2

Syntax

Description of the illustrationnvl2.gif

Purpose

 

NVL2 lets you determine the value returnedby a query based on whether a specified expression is null or notnull. Ifexpr1 is not null, thenNVL2 returnsexpr2. If expr1 is null, thenNVL2 returnsexpr3.--函数作用

 

The argument expr1 can have any datatype. Theargumentsexpr2 andexpr3 can have any datatypesexceptLONG.

If the datatypes of expr2 andexpr3 are different:

• If expr2 is character data, thenOracle Database convertsexpr3 to the datatype ofexpr2 before comparing themunlessexpr3 is a null constant. Inthat case, a datatype conversion is not necessary. Oracle returnsVARCHAR2 in the character set ofexpr2.

• If expr2 is numeric, then Oracledetermines which argument has the highest numeric precedence,implicitly converts the other argument to that datatype, andreturns that datatype.