Question

我有一个“游戏”表，其中包含player_id和player_action。

player_id | player_action  
1         | move  
1         | move  
1         | attack  
2         | attack  
2         | attack  
3         | move  
3         | move

我必须让所有玩家都采取“移动”动作但每个玩家只有一行，结果应该是

1  |  move  
3  |  move

有人会知道如何实现这个目标吗？

Answer 1

看起来您打算执行以下操作：

SELECT
    player_id, player_action
FROM
    games
WHERE
    player_action = 'move'
GROUP BY
    player_id

Answer 2

select distinct player_id, player_action from games where player_action = "move"

Answer 3

使用DISTINCT子句：

SELECT DISTINCT player_id, player_action FROM games WHERE player_action = 'move';

distinct子句将删除重复记录。（我相信还有很多其他解决方案。）

为条件选择一条记录

3 个答案: