从SELECT语句中的同一个表中获取两个项目

Question

我是一个SQL SELECT语句我需要提取两个团队的名称，从同一个表中获取两个团队。例如

SELECT sport_activity_id, (team A), (team B), date, time 
FROM sportactivity, teams 
WHERE competition_id_fk = 2

对于（团队A）和（团队B）我有一个team_id，这是表'团队'的FK

是否可以通过SQL从这些表中获得以下结果？ 1，巴塞罗那，阿森纳，01/01 / 2000,20：00

这两个表如下：

表格运动

sport_activity_id, home_team_fk, away_team_fk, competition_id_fk, date, time

（元组示例） - ＆gt; 1,33,41,5,2010-04-04,05：40：00

表团队

team_id, team_name

（元组示例） - ＆gt; 1，阿尔及利亚

Answer 1

是的，你只需要两次加入团队：

SELECT sport_activity_id, T1.team_name, T2.team_name, date, time 
FROM sportactivity
JOIN teams T1 ON home_team_fk = T1.team_id
JOIN teams T2 ON away_team_fk = T2.team_id
WHERE competition_id_fk = 2

Answer 2

SELECT sport_activity_id, teamA.team_Name, teamB.team_Name, date, time 
FROM sportactivity
INNER JOIN teams teamA ON sportactivity.home_team_fk = teamA.team_ID
INNER JOIN teams teamB ON sportactivity.away_team_fk = teamB.team_ID
WHERE competition_id_fk = 2