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Ankit Singh

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Posted on    November-08-2015 10:02 PM

 .NET SQL Server 
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i wnat to use Case Expression in sqlserver.please help me. 


aditya kumar Patel

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Posted on    November-08-2015 10:23 PM

Sometimes, you required to fetch or modify the records based on some conditions. In this case, you may use cursor or loop for modify your records. In this situation Case expression is best alternative for Cursor/looping and also provides better performance.
You can use CASE expressions anywhere in the SQL Query like CASE expressions can be used with in SELECT statement, WHERE clauses, Order by clause, HAVING clauses,Insert, UPDATE and DLETE statements.
This compares an expression to a set of simple expressions to find the result. This expression compares an expression to the expression in each WHEN clause for equivalency. If the expression with in the WHEN clause is matched, the expression in the THEN clause will be returned.

 

Syntax:

   CASE expression

WHEN expression1 THEN Result1

WHEN expression2 THEN Result2

ELSE ResultN

END

Example :

select CustomerID,CustomerName,Address,City,PostalCode,Country,

(case when CustomerID=1 then 'First Record'

when CustomerID=2 then 'Second Record' end) expcase    from Customer

 


 

 


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