Question

我有一个＆＃34;目标＆＃34;足球联赛的桌子。我的桌子包含＆＃34;目标玩家＆＃34;和＃34;目标助手＆＃34;，像这样：

Select idgoal, goal_player, goal_assist from myDB.goal LIMIT 3;

+--------+-------------+-------------+
| idgoal | goal_player | goal_assist |
+--------+-------------+-------------+
|      1 |          14 |          15 |
|      2 |          16 |           0 |
|      3 |          17 |          18 |
+--------+-------------+-------------+

goal_player和goal_assist下的ID都指我的玩家中的特定玩家＆＃34;表。在rder以可更新的方式呈现我的结果我必须替换实际名称的ID，所以我正在做：

SELECT idgoal, player.player_nickname as goal_player, goal_assist 
   FROM myDB.goal 
   JOIN player 
   ON goal_player = player.idplayer LIMIT 3;

+--------+-------------+-------------+
| idgoal | goal_player | goal_assist |
+--------+-------------+-------------+
|      1 | Maxi        |          15 |
|      2 | El Loco     |           0 |
|      3 | El Bebe     |          18 |
+--------+-------------+-------------+

我无法为goal_player和goal_assist执行此操作，因为这意味着同一个玩家同时执行目标和协助，所以我所做的是使用第一个Join创建一个视图，然后创建第二个视图使用第一个视图，替换＆＃34; goal_assist＆＃34;

像魅力一样工作，直到我必须对拥有match_id的名单和22名玩家而不是这些2做同样的事情。

那么，当两列都指向同一个表时，如何用原始表中的值替换ID？

Answer 1

您正在寻找两个联接。。。以及别名：

SELECT g.idgoal, p.player_nickname as goal_player,
       pa.player_nickname as assist_player 
FROM myDB.goal g JOIN
     player p
     ON g.goal_player = p.idplayer LET JOIN
     player pa
     ON g.goal_assist = pa.idplayer
LIMIT 3;

注意：

所有表都有别名。
所有列引用均为＆＃34;限定＆＃34;，表示它们引用列所在的表。
你需要两个连接。
第二次加入是LEFT JOIN，用于处理目标没有＆＃34;协助＆＃34;播放器。

Answer 2

你可以试试这个：

SELECT 
    idgoal, 
    (SELECT player_nickname FROM player WHERE player.idplayer = goal_player) as `goal_player_name`,
    (SELECT player_nickname FROM player WHERE player.idplayer = goal_assist) as `goal_assist_name`,
FROM myDB.goal

如何显示指向mySQL中同一个表的两个不同列的值？

2 个答案: