I want to use CASE statement to update some records in sql server 2005

Question

UPDATE dbo.TestStudents  
SET LASTNAME = 
( CASE  
WHEN (LASTNAME = \'AAA\') THEN \'BBB\' 
WHEN (LASTNAME = \'CCC\') THEN \'DDD\' 
WHEN (LASTNAME = \'EEE\') THEN \'F         


        

Answer 1

Add a WHERE clause

UPDATE dbo.TestStudents  
SET     LASTNAME =  CASE  
                        WHEN LASTNAME = 'AAA' THEN 'BBB' 
                        WHEN LASTNAME = 'CCC' THEN 'DDD' 
                        WHEN LASTNAME = 'EEE' THEN 'FFF' 
                        ELSE LASTNAME
                    END 
WHERE   LASTNAME IN ('AAA', 'CCC', 'EEE')