每个派生表都必须有自己的别名 mysql 错误消息答案

【问题标题】：Every derived table must have its own alias mysql error message每个派生表都必须有自己的别名 mysql 错误消息
【发布时间】：2017-02-18 13:02:38
【问题描述】：

我有以下查询，但我不确定在哪里需要别名，任何人都可以帮助防止我遇到的错误

// 错误

Every derived table must have its own alias

// 查询

SELECT user_id, 
       SUM(win) as won, SUM(draw) As drawn, SUM(loss) as lost, 
       SUM(goals_for) as goals_for, SUM(goals_against) as goals_against, 
       SUM(goals_for) - SUM(goals_against) as goals_difference, 
       player, username, community_result_id, count(*) as played, 
       SUM(points) as points     
FROM 
    ( SELECT home_team_user_id as user_id, 
      CASE WHEN home_score > away_score THEN 1 ELSE 0 END as win, 
      CASE WHEN home_score = away_score THEN 1 ELSE 0 END as draw, CASE 
      WHEN home_score < away_score THEN 1 ELSE 0 END as loss,
      CASE WHEN home_score > away_score THEN 3 
  WHEN home_score = away_score THEN 1 ELSE 0 END points,
       home_score as goals_for, away_score as goals_against,
       users.name as player, users.username, 
       community_results.community_result_id FROM community_results 
     LEFT JOIN users ON community_results.home_team_user_id=users.id 
     UNION ALL SELECT away_team_user_id as user_id, 
     CASE WHEN away_score > home_score THEN 1 ELSE 0 END as win, 
     CASE WHEN away_score = home_score THEN 1 ELSE 0 END as draw, 
     CASE WHEN away_score < home_score THEN 1 ELSE 0 END as loss, 
     CASE WHEN home_score > away_score THEN 3 WHEN home_score = away_score 
     THEN 1 ELSE 0 END points, away_score as goals_for, home_score as goals_against, 
     users.name as player, users.username, 
     community_results.community_result_id FROM community_results 
     LEFT JOIN users ON community_results.away_team_user_id = users.id ) 
     WHERE user_id = 1 GROUP BY user_id ORDER By won desc LIMIT 1

【问题讨论】：

当查询请求别名时，一种解决方案是给它一个

标签： mysql subquery left-join alias

【解决方案1】：

试试这个：

SELECT user_id, 
       SUM(win) as won, SUM(draw) As drawn, SUM(loss) as lost, 
       SUM(goals_for) as goals_for, SUM(goals_against) as goals_against, 
       SUM(goals_for) - SUM(goals_against) as goals_difference, 
       player, username, community_result_id, count(*) as played, 
       SUM(points) as points     
FROM 
    ( SELECT home_team_user_id as user_id, 
      CASE WHEN home_score > away_score THEN 1 ELSE 0 END as win, 
      CASE WHEN home_score = away_score THEN 1 ELSE 0 END as draw, CASE 
      WHEN home_score < away_score THEN 1 ELSE 0 END as loss,
      CASE WHEN home_score > away_score THEN 3 
  WHEN home_score = away_score THEN 1 ELSE 0 END points,
       home_score as goals_for, away_score as goals_against,
       users.name as player, users.username, 
       community_results.community_result_id FROM community_results 
     LEFT JOIN users ON community_results.home_team_user_id=users.id 
     UNION ALL SELECT away_team_user_id as user_id, 
     CASE WHEN away_score > home_score THEN 1 ELSE 0 END as win, 
     CASE WHEN away_score = home_score THEN 1 ELSE 0 END as draw, 
     CASE WHEN away_score < home_score THEN 1 ELSE 0 END as loss, 
     CASE WHEN home_score > away_score THEN 3 WHEN home_score = away_score 
     THEN 1 ELSE 0 END points, away_score as goals_for, home_score as goals_against, 
     users.name as player, users.username, 
     community_results.community_result_id FROM community_results 
     LEFT JOIN users ON community_results.away_team_user_id = users.id ) t
     WHERE user_id = 1 GROUP BY user_id ORDER By won desc LIMIT 1

【讨论】：