我有 3 张桌子:
顾客
ID_CUSTOMER
NAME
产品
ID_PRODUCT
PRODUCTNAME
PRICE
订单
ID_ORDER
CUSTOMER_ID
PRODUCT_ID
QUANTITY
如何选择所有订购 $10k 或以上的客户?
select c.*
from customers c
inner join orders o on o.customer_id = c.id_customer
inner join products p on p.id_product = o.product_id
group by c.id_customer
having sum(p.price * o.quantity) >= 10000
尝试类似:
SELECT C.ID_CUSTOMER, C.Name,
SUM(P.PRICE * O.QUANTITY) AS Total FROM Customers C
JOIN Orders O ON C.CUSTOMER_ID = O.CUSTOMER_ID
JOIN Procucts P ON P.PRODUCT_ID = O.PRODUCT_ID
GROUP BY C.ID_CUSTOMER, C.Name
HAVING SUM(P.PRICE * O.QUANTITY) >= 10000
试试这个:
SELECT a.ID_CUSTOMER,
a.NAME
FROM CUSTOMERS a
INNER JOIN ORDERS b
ON b.CUSTOMER_ID = a.ID_CUSTOMER
INNER JOIN PRODUCTS c
ON c.ID_PRODUCT = b.product_id
GROUP BY a.ID_CUSTOMER, a.NAME
HAVING SUM(c.PRICE * b.QUANTITY) >= 10000
这并不是一个复杂的查询。做同样事情的另一种语法:
SELECT C.ID_CUSTOMER, C.NAME, SUM(P.PRICE * O.QUANTITY) TOTAL
FROM Products P, Customers C, Orders O
WHERE O.CUSTOMER_ID = C.ID_CUSTOMER
AND O.PRODUCT_ID = P.ID_PRODUCT
GROUP BY C.ID_CUSTOMER, C.NAME
HAVING SUM(P.PRICE * O.QUANTITY) >= 10000