MySQL更新表，其中包含來自同一個表的值

Question

我有一個4列表，主鍵是id，gameId和flag的組合。

id | gameId | score | flag
--------------------------
1  | 1      | 10    | 1
1  | 1      | 20    | 0
2  | 1      | 1     | 0
1  | 2      | 10    | 1
3  | 2      | 1     | 0

我需要更新表格，以便：

• 所有gameId 2分數都被添加到gameId 1，其中id和flag是相同的。 （例如，通過添加第1行和第4行的分數，第1行的得分為20）

• 如果發生上述情況，則需要刪除gameId 2行。

• 如果沒有找到上面的內容（例如，有一行gameId為2，但id和flag與另一行不匹配），則gameId可以改為1。

因此SQL完成后我的表應如下所示：

id | gameId | score | flag
--------------------------
1  | 1      | 20    | 1
1  | 1      | 20    | 0
2  | 1      | 1     | 0
3  | 1      | 1     | 0

我怎么能在SQL中寫這個？ 謝謝 ：）

Answer 1

認為這會起作用：

試試1

UPDATE score_list AS t2
LEFT JOIN score_list AS t1 ON
  (t1.id = t2.id AND t1.flag = t2.flag AND t1.gameId = 1)
SET
  t1.score = t1.score + t2.score,
  t2.gameId = IF(t1.gameId IS NULL, 1, t2.gameId)
WHERE t2.gameId = 2;

DELETE FROM score_list WHERE gameId = 2;

試試2

# add scores to gameId = 1
UPDATE score_list AS t2
LEFT JOIN score_list AS t1 ON
  (t1.id = t2.id AND t1.flag = t2.flag AND t1.gameId = 1)
SET
  t1.score = t1.score + t2.score
WHERE t2.gameId = 2;

# try to move gameID 2 to gameId 1, using ignore to allow rows to fail, as gameId alredy exists
UPDATE IGNORE score_list SET gameId = 1 WHERE gameId = 2;

# delete all not updated rows from last query
DELETE FROM score_list WHERE gameId = 2;