选择多行

Question

我有2张桌子

Product
------------------------------
productID | productName
------------------------------
1  | Banana
2  | Apple
3  | Pie
4  | Dragon Fruit
5  | Watermelon
6  | Kiwi
7  | Nugget

Purchase
-------------------------------------
purchaseID | productID | purchaserID
-------------------------------------
1          |1          |1
2          |2          |1
3          |3          |1
4          |4          |2
5          |5          |2
6          |2          |4
7          |1          |5

如何从购买表中购买购买产品ID 1和2和3的购买者ID（购买者ID 1）？ TYVM！

Answer 1

这是＆＃34; set-within-sets＆＃34;查询。灵活的方法是使用group by和having：

select purchaserId
from purchases
where productid in (1, 2, 3)
group by purchaserId
having count(distinct productid) = 3;