SQLZOO 第六套英文（困难版）The JOIN operation

最新推荐文章于 2025-01-28 02:00:00 发布

原创最新推荐文章于 2025-01-28 02:00:00 发布 · 264 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#sqlzoo #答案 #join #六

SQL 专栏收录该内容

4 篇文章

订阅专栏

本文精选了13个SQL查询实例，涵盖从显示特定比赛进球球员到每场比赛中各队伍进球数的复杂查询，深入探讨了如何利用JOIN、GROUP BY、CASE WHEN等SQL语句进行高效的数据筛选与汇总。

8.Instead show the name of all players who scored a goal against Germany.

SELECT distinct player
FROM game JOIN goal ON matchid = id 
WHERE (team1='GER' or team2='GER')
and teamid != 'GER'

9.Show teamname and the total number of goals scored.

SELECT teamname, count(teamid)
FROM eteam JOIN goal ON id=teamid
group by teamname

10.Show the stadium and the number of goals scored in each stadium.

select stadium, count(player)
from game join goal on game.id = goal.matchid
group by stadium

11.For every match involving 'POL', show the matchid, date and the number of goals scored.

SELECT matchid,mdate, count(teamid)
FROM game JOIN goal ON matchid = id 
WHERE (team1 = 'POL' OR team2 = 'POL')
group by matchid,mdate

12.For every match where 'GER' scored, show matchid, match date and the number of goals scored by 'GER'

select matchid, mdate, count(teamid)
from game join goal on id = matchid
where teamid = 'GER'
group by matchid,mdate

13.List every match with the goals scored by each team as shown. This will use "CASE WHEN" which has not been explained in any previous exercises.

SELECT mdate,
  team1,sum(
  CASE WHEN teamid=team1 THEN 1 ELSE 0 END ) as score1,
team2,sum(
  CASE WHEN teamid=team2 THEN 1 ELSE 0 END ) as score2
  FROM game left JOIN goal ON matchid = id
group by mdate,matchid,team1,team2