如何从SQL的表中选择，其中一列中的元素仅包含另一列的特征，而另一列本身又包含两个特征？

Question

可以说我在SQL中有一个table1，如下所示。

Team   PlayerID

Team1  12
Team2  56
Team1  78
Team1  96
Team3  23
Team2  45
Team3  89
Team3  78

现在我有一个新的table2作为

PlayerID  Gender

12        Male
56        Female
78        Female
96        Male
23        Female
45        Male
89        Female
78        Female

有没有办法列出所有只有女性的球队？

Answer 1

您可以使用join ， group by和having ：

select t.team
from teams t join
     players p
     on p.playerid = t.playerid
group by t.team
having min(gender) = max(gender) and min(gender) = 'Female';

Answer 2

如果您确定每队至少有1名球员，那么这应该可行：

SELECT T1.Team
FROM Table1 T1
LEFT JOIN Table2 T2 ON T1.PlayerID = T2.PlayerID AND t2.Gender = 'Male'
GROUP BY T1.Team
Having COUNT(Gender) = 0