Question

我有这个SQL查询的问题，查询是自我解释的，所以看着它会告诉你我有什么问题

SELECT customer.customerid, 
       paymentdata.paidamount, 
       paymentdata.balanceamount, 
       sum(paymentreceipt.paidamount) AS Expr1 
FROM   customer 
       INNER JOIN paymentdata 
               ON customer.customerid = paymentdata.customerid 
       INNER JOIN paymentreceipt 
               ON customer.customerid = paymentreceipt.customerid 
GROUP  BY customer.customerid

Answer 1

您的小组中缺少一些条款。需要包括除聚合列之外的所有列。

Answer 2

那么你想如何计算其他列，你只是按customerid进行分组，但是你想要同时显示paymentdata.paidamount，paymentdata.balanceamount和paymentreceipt.paidamount？

考虑该组为每个组返回多行，因此sql-server（或除MySql之外的任何其他rdbms）不知道您要为未分组列显示哪一行。如果您不想选择单行，则必须聚合该列。所以例如使用SUM，COUNT，MAX或AVG：

例如：

SELECT customer.customerid, 
       MAX(paymentdata.paidamount) AS MaxPaid, 
       AVG(paymentdata.balanceamount) AS AverageBalance, 
       SUM(paymentreceipt.paidamount) AS ReceiptPaidSum
FROM   customer 
       INNER JOIN paymentdata 
               ON customer.customerid = paymentdata.customerid 
       INNER JOIN paymentreceipt 
               ON customer.customerid = paymentreceipt.customerid 
GROUP  BY customer.customerid

Answer 3

您需要对group by子句

中未使用的列使用聚合函数

SELECT customer.customerid, 
       sum(paymentdata.paidamount), 
       sum(paymentdata.balanceamount), 
       sum(paymentreceipt.paidamount) AS Expr1 
FROM   customer 
       INNER JOIN paymentdata 
               ON customer.customerid = paymentdata.customerid 
       INNER JOIN paymentreceipt 
               ON customer.customerid = paymentreceipt.customerid 
GROUP  BY customer.customerid

Answer 4

SELECT customer.customerid,paymentdata.customerid,paymentreceipt.customerid  
       paymentdata.paidamount, 
       paymentdata.balanceamount, 
       paymentreceipt.paidamount AS Expr1 
FROM   customer,paymentdata,paymentreceipt
       INNER JOIN paymentdata 
               ON customer.customerid = paymentdata.customerid 
       INNER JOIN paymentreceipt 
               ON customer.customerid = paymentreceipt.customerid 
GROUP  BY customer.customerid,paymentdata.customerid,paymentreceipt.customerid

Answer 5

如果您正在进行聚合，那么您可能需要聚合函数：

SELECT customer.customerid, 
       sum(paymentdata.paidamount), 
       sum(paymentdata.balanceamount), 
       sum(paymentreceipt.paidamount) AS Expr1 
FROM   customer 
       INNER JOIN paymentdata 
               ON customer.customerid = paymentdata.customerid 
       INNER JOIN paymentreceipt 
               ON customer.customerid = paymentreceipt.customerid 
GROUP  BY customer.customerid

这可能仍然无法为您提供正确的数字，因为您正在获得付款和收据的交叉加入。如果您想要更好的答案，那么您应该在问题中提供样本数据和预期结果。

带有Group by子句的SQL Query，带有sum聚合

5 个答案: