查询订单表里有且仅购买空调和洗衣机的订单数with a as ( select orderid, count(distinct category) from tbl_order group by orderid having count(distinct category) = 2 )select count(distinct a.orderid)from aleft join tbl_order as o on a.orderid = o.orderidand category in ('空调', '洗衣机')