mysql - 如何限制INNER JOIN？

Question

您好，有没有办法限制我的内部连接？

所以我可以限制输出只返回最后 5 个 match_ids？

SELECT t.id
     , ff.match_id
     , ff.time
  FROM football_teams t
  JOIN 
     ( SELECT match_id
            , hometeam_id
            , time
         FROM football_fixtures 
        ORDER 
           BY time DESC 
        LIMIT 5
     ) ff
    ON ff.hometeam_id = t.id
 WHERE t.id IN ( ".$team_id_string." ) 
 ORDER 
    BY t.id

我观察返回一个数组

像这样的

array([football_team.id] = array(match_id[1],match_id[2],match_id[3],match_id[4],match_id[5],))

马特

Answer 1

根据评论，我假设 football_fixtures 表中的 5 条最新记录与您查询中的其他条件不匹配，因此 - 不返回任何内容。我建议在外部查询中设置限制以确保选择了 5 条记录:

SELECT s.* FROM 
    (SELECT 
            football_teams.id,
            ff.match_id,
            ff.time
            FROM football_teams 
    INNER JOIN football_fixtures ff
     ON hometeam_id=football_teams.id
    WHERE football_teams.id IN ( ".$team_id_string." )
    ORDER BY ff.time
    LIMIT 5) s
ORDER BY s.id