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NVL2

Syntax

Description of the illustration nvl2.gif

Purpose

NVL2 lets you determine the value returned by a query based on whether a specified expression is null or not null. If expr1 is not null, then NVL2 returns expr2. If expr1 is null, then NVL2 returns expr3.--函数作用

The argument expr1 can have any datatype. The arguments expr2 and expr3 can have any datatypes except LONG.

If the datatypes of expr2 and expr3 are different:

• If expr2 is character data, then Oracle Database converts expr3 to the datatype of expr2 before comparing them unless expr3 is a null constant. In that case, a datatype conversion is not necessary. Oracle returns VARCHAR2 in the character set of expr2.

• If expr2 is numeric, then Oracle determines which argument has the highest numeric precedence, implicitly converts the other argument to that datatype, and returns that datatype.