将 WHERE 子句与 GROUP BY 一起使用

Using WHERE CLAUSE with GROUP BY

我想用 2 tables -

显示每张账单的售出商品总价值

这里是table项,table的结构是I_Code->int,Name->Varchar,Category->Varchar,Rate->int

这是table bills,table的结构是BillNo->int,Date->date, I_Code->整数, 数量->整数

这是我试图获得所需输出的查询

SELECT i.`rate` * b.`qty`, b.`BillNo` FROM bills b, items i WHERE b.I_Code=i.I_Code GROUP BY `BillNo` ;

但是输出不正确

预期输出

试试这个:

SELECT SUM(A.TOT), b.`BillNo`
FROM (
    SELECT i.`rate` * b.`qty` AS TOT, b.`BillNo`
    FROM bills b, items i
    WHERE b.I_Code = i.I_Code
) AS A
GROUP BY `BillNo`;

SELECT SUM(i.`rate` * b.`qty`) AS TOT, b.`BillNo`
FROM bills b, items i
WHERE b.I_Code = i.I_Code
GROUP BY `BillNo`;