select 产品ID,产品名称,分类ID,分类名称 from (select a.分类ID,a.分类名称,c.产品ID,c.产品名称 from (select 分类ID,分类名称 from 分类表 where 分类 in(1,2,3)) a inner join 产品分类表 b on a.分类ID=b.分类ID inner join 产品表 c b.产品ID=c.产品ID)
--如果已知分类1、分类2 是分类名称
select * from 产品表 where 产品ID in
(select 产品ID
from 产品分类表 a inner join 分类表 b on a.分类ID = b.分类ID
where b.分类名称 = '分类1' or b.分类名称 = '分类2' or b.分类名称 = '分类3'
group by 产品ID having count(1) = 3
)
--如果已知分类1、分类2 是分类ID
select * from 产品表 where 产品ID in
(select 产品ID
from 产品分类表 b
where b.分类id = '分类1' or b.分类ID = '分类2' or b.分类ID = '分类3'
group by 产品ID having count(1) = 3
)