嵌套子查詢可從多個表中選擇

Question

我有三張桌子：

Years (YearId,Year)
Months (MonthID,Month)
Date (DateID,YearID,MonthID)
Client (CLientID,ClientName)
Payment (PayID,ClientID,DateID,Amount)

我想填寫DataGridView：

Client Name, Amount, Year, Month 

我使用了這個聲明，但它不起作用：

Select * From (select Year From Years Where YearID = (Select YearId From Date Where dateID = (Select DateID From Payment))),(Select Month From Months Where Monthid = (Select MonthID From Date Where dateID = (Select DateID From Payment))),(Select ClientName From Client Where ClientID = (Select ClientID From Payment),(Select amont From Payment)

Answer 1

聽起來你只是想使用INNER JOINs ：

SELECT C.ClientName,
    P.Amount,
    Y.Year,
    M.Month
FROM Payment P
    INNER JOIN Client C 
        ON P.ClientID = C.ClientID
    INNER JOIN Date D 
        ON P.DateId = D.DateId
    INNER JOIN Years Y
        ON D.YearId = Y.YearId
    INNER JOIN Months M
        ON D.MonthId = M.MonthId

請參閱下面的JOINs的良好直觀表示：

JOINS的視覺表示