左加入多个条件

Question

我有3个表格，即客户，信用和付款。我希望在@StartDate和@EndDate之间获得客户所做的所有付款和积分。这是我的查询：

SELECT   Client.Name, Payment.PaymentAmount, Credit.CreditAmount 
FROM   Client 

LEFT JOIN Payment 
ON Client.ClientID = Payment.ClientID 
LEFT JOIN Credit 
ON Client.ClientID = Credit.ClientID 

WHERE  (Payment.Date BETWEEN @StartDate AND @EndDate) AND (Client.Date BETWEEN @StartDate AND @EndDate) 
ORDER BY Client.CName 

我想说明，即使款项已经不反对它的信用和NULL作出付款的全部学分，反之亦然。但我无法得到它，因为它只显示当天有信用和付款的客户。

我试过OR而不是AND（与'WHERE'）但它不起作用。

Answer 1

你可以得到你想要的东西通过移动条件的on条款：

SELECT c.Name, p.PaymentAmount, cr.CreditAmount 
FROM Client c LEFT JOIN 
    Payment p 
    ON c.ClientID = p.ClientID AND p.Date BETWEEN @StartDate AND @EndDate LEFT JOIN 
    Credit cr 
    ON c.ClientID = cr.ClientID AND cr.Date BETWEEN @StartDate AND @EndDate 
ORDER BY c.CName; 

但是，我不知道这是你真的想什么，因为它是做一个笛卡尔积支付和信用之间，在这段时间内多于一个。

这可能就是更接近你真正想要的东西：

SELECT c.Name, p.PaymentAmount, NULL as CreditAmount 
FROM Client c LEFT JOIN 
    Payment p 
    ON c.client_id = p.ClientId AND p.Date BETWEEN @StartDate AND @EndDate 
UNION ALL 
SELECT c.Name, NULL, c.CreditAmount 
FROM Client c LEFT JOIN 
    Credit cr 
    ON c.ClientID = cr.ClientID AND cr.Date BETWEEN @StartDate AND @EndDate 
ORDER BY Name;