Update multiple rows with multiple 'where' clauses for each individual row

Question

I am trying to update my table like this:

Update MyTable 
SET value     = 1 
WHERE game_id = 1,
      x       =-4,
      y       = 8

SET value     = 2 
WHER         


        

Answer 1

give this a try by using CASE

Update  MyTable 
SET     value = CASE 
                     WHEN  game_id = 1 AND x = -4 AND y = 8 THEN 1
                     WHEN  game_id = 1 AND x = -3 AND y = 7 THEN 2
                     WHEN  game_id = 2 AND x =  5 AND y = 2 THEN 3
                     ELSE  value 
                END
WHERE   game_ID IN (1,2,3) AND  -- the purpose of this WHERE clause
        x IN (-4, -3, 5) AND    -- is to optimize the query by preventing from
        y IN (8,7,2)            -- performing full table scan.