求一个sql语句

Question

表一                                             表二
shopcar                                            orders
shopcar_id  orders_id   food_number               ordes_id     orders_name  state
1             2           3                         2                aa       0
2             2           4                         3                 bb      0
3             4           2                         4                 cc      1
其中shopcar中的orders_id是orders表的外键根据表orders中orders_id等于2和state等于0结果是
2       7

Answer 1

试试：
SELECT shopcar.orders_id, SUM(food_number)
FROM shopcar, orders
WHERE shopcar.orders_id = orders.orders.id AND state = 0
GROUP BY shopcar.orders.id

Answer 2

算了 拿去吧SELECT shopcar.orders_id, SUM(food_number)
FROM shopcar, orders
WHERE shopcar.orders_id = orders.orders_id AND state = 0
GROUP BY shopcar.orders_id

Answer 3

可以了，是我少写了 s.orders_id = o.orders_id
 谢谢你了