SQL加入两个集团的表

Question

我是新来的数据库等世界开发商谁让我的店的POS花了很大一笔钱，不会回答我。我需要在季度末报告我的应收账款。请在访问中帮助查询此查询。我尝试了离开加入，当我只加入购物，但没有购买和付款时，它工作正常。

TABLES：

CUSTOMERSTABLE: 
CUSTOMERID**********NAME 

PURCHASESTABLE: 
SALEID**********CUSTOMERID**********AMOUN******TDATE 

PAYMENTSTABLE: 
PAYMENTSID**********customerid*********amount******TDATE 

结果应显示所有customerids（可用transations与否），购买的每个的总量，对于每个支付的总金额，余额（净两个），它应该只给定TDATE之前考虑交易

Answer 1

SELECT cust.customerid, Sum(purch.Amount_charged) AS totalPurchases, Sum(pay.Payment_Made) AS SumOfPayment_Made 
FROM (cust INNER JOIN pay ON cust.customerid = pay.Account_Id) INNER JOIN purch ON cust.customerid = purch.Account_Id 
WHERE ((([purch].[TDATE]) Between '4/6/2015' And '5/18/2015')) 
GROUP BY cust.customerid;