Check Null Value in SQL Server 2005

Below SQL Query is used to Check null Value in SQL Server 2005.

Syntax

IFNULL(ColumnName,0)

Example

select (case when ISNULL((Select sum(Amount) From Payment B Where B.Purchase_RefID=Purchase.Purchase_RefID  and Status in('Active')),'0') <>'0' THEN  (Select  sum(Amount)  From Payment B Where B.Purchase_RefID=Purchase.Purchase_RefID  and Status in('Active')) else '0' end ) as PaidAmount