1. inner join：

在店鋪表中找到含商品表中所有商品的店鋪：

select shopfrom items,shopitemswhere items.item = shopitems.itemgroup by shophaving count(*) = (select count(*) from items)

---針對集合設(shè)定條件：inner join 過濾出品類相同的記錄；having 條件為聚合后兩表品類數(shù)一致。

2. outer join：

在店鋪表中找到僅含商品表中所有商品的店鋪：

select shopfrom shopitems left join itemson shopitems.item = items.itemgroup by shophaving count(items.item) = (select count(*) from items)

---對 left join 匹配到的右列品類計數(shù)，條件為與商品表品類數(shù)一致。?

?鏈接：https://www.dianjilingqu.com/530790.html