Question

我有三张A，B，C表。

我如何一次加入A和B以及B加C？

例如，如果我有这些表：订单，产品，用户，我想要这样的查询：

SELECT Product.title, User.username, Order.id
FROM Order
/* with this condition: */
Order.ProductID = Product.ID
Product.UserID = User.ID

Answer 1

在from子句中组合联接：

select * 
  from aaa a inner join bbb b
     on a.x = b.y
  inner join ccc c
     on b.x = c.y

Answer 2

尝试：

SELECT Product.title, User.username, Order.id
FROM Order
INNER join Product ON Order.ProductID = Product.ID
INNER JOIN user ON Product.UserID = User.ID

Answer 3

select * from A a join B a on a.id = b.id /* condition for join*/ join C c on A.id = c.id /* condition for join*/ where ;//condition

我怎样才能一次加入A和B以及B加C？

3 个答案: