Question

有两列，我想减去它们。我正在尝试对[付款]列求和，然后从[total_bill]列中减去它。下面是我的代码，它给了我一个错误，它无法对包含聚合或子查询的表达式执行聚合函数。

SELECT SUM((bill_record.total_bill)-SUM(invoice_payments.payment)) AS [LEFT AMOUNT]

Answer 1

您需要使用分组方式，但是您可能只想对付款进行总计，然后从单个总账单中减去付款。

SELECT bill_record.total_bill - SUM(invoice_payments.payment) AS [LEFT AMOUNT] 
FROM bill_record INNER JOIN invoice_payments ON bill_record.PKColumn = invoice_payments.FKColumn 
WHERE bill_record.PKColumn = @billId
GROUP BY bill_record.total_bill

请注意，此处的group by起作用，因为您也在WHERE子句中进行过滤。如果要获取多个账单的结果，还可以按唯一的账单标识符分组，并将其返回到SELECT中。

SELECT bill_record.PKColumn AS BillId, bill_record.total_bill - SUM(invoice_payments.payment) AS [LEFT AMOUNT] 
FROM bill_record INNER JOIN invoice_payments ON bill_record.PKColumn = invoice_payments.FKColumn 
GROUP BY bill_record.PKColumn, bill_record.total_bill

Answer 2

您似乎想要一个sum而不是两个：

SELECT SUM(bill_record.total_bill - invoice_payments.payment) AS [LEFT AMOUNT]
FROM . . .

Answer 3

在您的请求中，从...中选择项目。该请求应类似于

SELECT SUM((bill_record.total_bill)-SUM(invoice_payments.payment)) AS [LEFT AMOUNT] FROM YOUR TABLE NAME

Answer 4

db.CreateCollection("users")

Answer 5

在使用SUM聚合函数时，必须正确使用group by子句

和选择列数必须在group by子句上

SELECT SUM((bill_record.total_bill)-SUM(invoice_payments.payment)) AS [LEFT AMOUNT]

错误的出处可以在列的子句编号中进行分组，否则查询将起作用

从SQL查询中的两列中减去值

5 个答案: