MySQL更新表,其中包含来自同一个表的值

Question

我有一个4列表,主键是id,gameId和flag的组合.

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分数都被添加到gameId 1,其中id和flag是相同的.(例如,通过添加第1行和第4行的分数,第1行的得分为20)

• 如果发生上述情况,则需要删除gameId 2行.

• 如果没有找到上面的内容(例如,有一行gameId为2,但id和flag与另一行不匹配),则gameId可以改为1.

因此SQL完成后我的表应如下所示:

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中写这个？谢谢 :)

Answer 1

认为这会起作用:

试试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;

试试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;