sql [db2] select条件语句

Question

我有两张桌子。
player1具有用户名，分数，game_id等行...
player2包含用户名，得分，game_id ...
如何为相同的game_id选择得分最高的用户名？

我所拥有的是

SELECT player1.username winning,
  player1.points,
  player1.game_id 
FROM player1 
INNER JOIN player2 ON player1.game_id = player2.game_id
WHERE player1.points > player2.points

和

SELECT player2.username winning,
  player2.points,
  player2.game_id 
FROM player1 
INNER JOIN player2 ON player1.game_id = player2.game_id
WHERE player2.points > player1.points  

Answer 1

应该这样做：

SELECT
    game_id, 
    CASE WHEN p1.score > p2.score THEN p1.username ELSE p2.username END AS winner
FROM
    player1 p1
INNER JOIN
    player2 p2 ON p1.game_id = p2.game_id
ORDER BY 
    p1.game_id ASC

如Darius所述，您可能希望根据Draw的情况调整CASE语句，您可以将其更改为以下形式：

CASE WHEN p1.score > p2.score THEN p1.username WHEN p1.score < p2.score THEN p2.username ELSE 'Draw' END AS winner

这实际上取决于您要在那种情况下显示什么。