Conditional Operator in SQL Where Clause

Question

I\'m wishing I could do something like the following in SQl Server 2005 (which I know isnt valid) for my where clause. Sometimes @teamID (passed into a stored procedure) wi

Answer 1

Without using dynamic SQL, the most performant option is:

IF @teamid = 0
  BEGIN

    SELECT t.teamid
      FROM TEAM t
     WHERE t.teamid > 0

  END
ELSE
  BEGIN

    SELECT t.teamid
      FROM TEAM t
     WHERE t.teamid = @teamid

  END

Using Dynamic SQL:

DECLARE @SQL NVARCHAR(4000)
   SET @SQL = 'SELECT t.teamid
                 FROM TEAM t
                WHERE 1 = 1 '

   SET @SQL = @SQL + CASE @teamid
                       WHEN 0 THEN ' AND t.teamid > 0 '
                       ELSE ' AND t.teamid = @teamid '
                     END

BEGIN

  EXEC sp_EXECUTESQL @SQL N'@teamid INT', @teamid

END

Beware that sp_EXECUTESQL caches the query plan, while EXEC will not. Read this: http://www.sommarskog.se/dynamic_sql.html