连接两个选择语句 [英] joining two select statements

问题描述

谁能告诉我以下原因为什么不起作用?它抱怨两个选择之间的连接关键字附近存在语法错误.

Can anyone tell me why the following won't work? It complains of a syntax error near the join key word between the two selects.

SELECT * 
FROM ( select * from orders_products inner JOIN orders ON orders_products.orders_id = orders.orders_id  where products_id = 181) 
as A

join 

SELECT * 
FROM ( select * from orders_products INNER JOIN orders ON orders_products.orders_id = orders.orders_id  where products_id = 180) 
as B

on A.orders_id=B.orders_id

基本上，我的第一个SELECT从一个表中提取某个产品的所有订单信息，并从另一个表中提取订购数量，并将它们连接在一起.第二个SELECT对另一种产品执行相同的操作.

Basically my first SELECT pulls all the order info for a certain product from one table and pulls the quantity ordered from another and joins them together. The second SELECT does the same thing for another product.

现在，我有

_______A_________         _______B_________

O_ID   P_ID   Q            O_ID   P_ID   Q 

1       180   3            1       181   11

2       180   9            2       181   6

3       180   5            3       181   3

然后，我想使用另一个联接

And, using another join I want to get

Q_ID   P_ID1   Q1    P_ID2    Q2

1       180    3      181     11

2       180    9      181      6

3       180    5      181      3

也许我在这里采用了错误的方法.有什么建议吗?

Maybe I am taking a wrong approach here. Any suggestions?

更新: 这是RedFilter指针之后对我有用的东西:

UPDATE: Here is what worked for me after pointers by RedFilter:

(SELECT * 
FROM (
SELECT * FROM orders_products
INNER JOIN orders ON orders_products.orders_id = orders.orders_id
WHERE products_id =181) AS A
LEFT JOIN (
SELECT * FROM orders_products
INNER JOIN orders ON orders_products.orders_id = orders.orders_id
WHERE products_id =180) AS B ON A.orders_id = B.orders_id
)
UNION (
SELECT * 
FROM (
SELECT * 
FROM orders_products
INNER JOIN orders ON orders_products.orders_id = orders.orders_id
WHERE products_id =181
) AS C
RIGHT JOIN (
SELECT * 
FROM orders_products
INNER JOIN orders ON orders_products.orders_id = orders.orders_id
WHERE products_id =180
) AS D ON C.orders_id = D.orders_id
) 

推荐答案

不确定要执行的操作，但是有两个select子句.改为执行此操作:

Not sure what you are trying to do, but you have two select clauses. Do this instead:

SELECT * 
FROM ( SELECT * 
       FROM orders_products 
       INNER JOIN orders ON orders_products.orders_id = orders.orders_id 
       WHERE products_id = 181) AS A
JOIN ( SELECT * 
       FROM orders_products 
       INNER JOIN orders ON orders_products.orders_id = orders.orders_id
       WHERE products_id = 180) AS B

ON A.orders_id=B.orders_id

更新:

您可能可以将其简化为以下形式:

You could probably reduce it to something like this:

SELECT o.orders_id, 
       op1.products_id, 
       op1.quantity, 
       op2.products_id, 
       op2.quantity
FROM orders o
INNER JOIN orders_products op1 on o.orders_id = op1.orders_id  
INNER JOIN orders_products op2 on o.orders_id = op2.orders_id  
WHERE op1.products_id = 180
AND op2.products_id = 181

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