Question

好的，我有三张表，Colors，People，Likes

Colors包含ID和名称颜色，People包含ID和人名，Likes包含color_id和people_id来描述哪些人喜欢哪种颜色

现在，给定一个颜色列表，我如何选择喜欢列表中每种颜色的每个人（如果有的话）？

Answer 1

select p.id, p.name
from people p
join likes l on l.people_id = p.id
join colors c on l.color_id = c.id
where c.name in ('blue','green','red')
group by p.id, p.name
having count(distinct c.name) = 3

Answer 2

您可以对喜欢加入的人进行GROUP BY，并检索那些具有等于颜色列表中行数的COUNT（*）的元组。这样你

只需要加入两个表
不需要明确命名颜色。

SELECT People.id, COUNT(*) AS ColorsLiked
    FROM People JOIN Likes ON (People.id = Likes.people_id)
GROUP BY People.id
HAVING ColorsLiked = (SELECT COUNT(*) FROM Colors);

Answer 3

SELECT * FROM People p 
INNER JOIN Likes l ON l.people_id = p.people_id 
INNER JOIN Colors c ON l.color_id = c.color_id 
WHERE c.name IN ('List of colors')

选择同时具有Y和Z的X（SQL）

3 个答案: