How to perform an IF…THEN in an SQL SELECT?

How do I perform an IF...THEN in an SQL SELECT statement?
For example:
SELECT IF(Obsolete = 'N' OR InStock = 'Y' ? 1 : 0) AS Saleable, * FROM Product


Answer:

The CASE statement is the closest to IF in SQL and is supported on all versions of SQL Server
SELECT CAST(
             CASE 
                  WHEN Obsolete = 'N' or InStock = 'Y' 
                     THEN 1 
                  ELSE 0 
             END AS bit) as Saleable, * 
FROM Product
You only need to do the CAST if you want the result as a boolean value, if you are happy with an int, this works:
SELECT CASE 
            WHEN Obsolete = 'N' or InStock = 'Y' 
               THEN 1 
               ELSE 0 
       END as Saleable, * 
FROM Product
CASE statements can be embedded in other CASE statements and even included in aggregates.
SQL Server Denali (SQL Server 2012) adds the IIF statement which is also available in access: (pointed out by Martin Smith)
SELECT IIF(Obsolete = 'N' or InStock = 'Y', 1, 0) as Saleable, * FROM Product


http://stackoverflow.com/questions/63447/how-to-perform-an-if-then-in-an-sql-select

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