具有特定产品的mysql订单

Question

我有3个表订单，orders_products和产品。我已加入他们以获取每个订单的产品..

SELECT o.orders_id, p.products_id, p.item_type 
from orders o 
join orders_products op on o.orders_id = op.orders_id 
join products p on op.products_id = p.products_id

现在我只想获得只有p.item_type = 1或p.item_type = 2的订单。（如果订单的产品类型为1,2和3，请勿显示，只有产品订单类型1或2）

Answer 1

如果您只想要订单，可以使用group by和having。以下是订单1和2以及其他订单：

select op.orders_id
from orders_products op join
     products p
     on op.products_id = p.products_id
group by op.orders_id
having sum(p.item_type = 1) > 0 and
       sum(p.item_type = 2) > 0 and
       sum(p.item_type not in (1, 2)) = 0;

请注意，不需要orders表。

您可以将此having子句用于1或2而不使用其他子句：

having sum(p.item_type in (1, 2) > 0 and
       sum(p.item_type not in (1, 2)) = 0;