Question

对不起，标题有些混乱，我不知道该如何表达。

我要解决的问题是，例如，我有2个表，GAMES和PLAYERS。 GAMES具有GAME_ID，PLAYER_1_ID，PLAYER_2_ID和WINNER_PLAYER_ID。 PLAYERS具有PLAYER_ID和PLAYER_NAME。我希望得到一个GAME_ID，PLAYER_1_NAME，PLAYER_2_NAME，WINNER_NAME的返回表，从{{1}基本上替换了ID列 }表及其名称。

我想我可以这样做，但是看起来太长了：

GAMES

我做对了吗，有没有更好，更有效的方法来解决此问题？

示例：

GAMES表：

select
  GAME_ID,
  PLAYER_1_NAME,
  PLAYER_2_NAME,
  WINNER_NAME
from
  (
    select
      temp2.*,
      PLAYERS.PLAYER_NAME as WINNER_NAME
    from(
        select
          temp1.*,
          PLAYERS.PLAYER_NAME as PLAYER_2_NAME
        from
          (
            select
              GAMES.*,
              PLAYERS.PLAYER_NAME as PLAYER_1_NAME
            from
              GAMES
              inner join PLAYERS on GAMES.PLAYER_1_ID = PLAYERS.PLAYER_ID
          ) temp1
          inner join PLAYERS on temp1.PLAYER_2_ID = PLAYERS.PLAYER_ID
      ) temp2
      inner join PLAYERS on temp2.WINNER_PLAYER_ID = PLAYERS.PLAYER_ID
  )

玩家表：

GAME_ID | PLAYER_1_ID | PLAYER_2_ID | WINNER_PLAYER_ID
1       | 1           | 3           | 3
2       | 2           | 3           | 3
3       | 1           | 3           | 1

预期返回什么：

PLAYER_ID | PLAYER_NAME
1         | Tom
2         | Sam
3         | Lucy

Answer 1

据我了解，下面是您的问题的解决方案；

SELECT GAME_ID,
  P1.PLAYER_NAME AS PLAYER_1_NAME,
  P2.PLAYER_NAME AS PLAYER_2_NAME,
  P3.PLAYER_NAME AS WINNER_NAME
FROM GAMES G 
LEFT JOIN PLAYERS P1 ON G.PLAYER_1_ID = P1.PLAYER_ID 
LEFT JOIN PLAYERS P2 ON G.PLAYER_2_ID = P2.PLAYER_ID 
LEFT JOIN PLAYERS P3 ON G.PLAYER_3_ID = P3.PLAYER_ID

在您共享示例之后，我确定这是正确的结果。

在SELECT结果中替换具有相同属性的列

1 个答案: