Divide by Subquery returning 'Subquery returned more than 1 value.' error

问题

I have the following table in which I have two sales orders and each sales order has a different number of transactions.

SaleOrder	Transaction	Amount
S1	T1	20
S1	T2	20
S2	T1	15
S2	T2	15
S2	T3	15

The problem is I am getting the total sales order amount against each transaction in SQL Server table when in fact they need to be divided equally among the number of transactions like this:

SaleOrder	Transaction	Amount
S1	T1	10
S1	T2	10
S2	T1	5
S2	T2	5
S2	T3	5

I've written the following query:

SELECT SalesOrder,
     Transaction,
     Max(Amount) / (SELECT COUNT(Transaction) AS Transaction FROM Test_Table GROUP BY SalesOrder)
    FROM Test_Table
    GROUP BY SalesOrder,
        Transaction

But it is giving me 'Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <=, >, >= or when the subquery is used as an expression.' error. Can someone explain what this is and how to rectify this error?

回答1:

I don't think you want group by, just window functions:

SELECT SalesOrder, Transaction,
       Amount) / COUNT(*) OVER (PARTITION BY salesorder)
FROM Test_Table;

回答2:

Since in the subquery you GROUP BY SalesOrder it returns 1 row for each SalesOrder.
But you want the number of transactions for the specific SalesOrder.
Use MAX() and COUNT() window functions:

SELECT DISTINCT SalesOrder, Transaction, 
       MAX(Amount) OVER (PARTITION BY SalesOrder, Transaction) / 
       COUNT(*) OVER (PARTITION BY SalesOrder)
FROM Test_Table

If the data type of the column Amount is INTEGER then SQL Server will perform integer division, so maybe you need to multiply first by 1.0 so that you get a correct result with decimal places:

SELECT DISTINCT SalesOrder, Transaction, 
       1.0 * MAX(Amount) OVER (PARTITION BY SalesOrder, Transaction) / 
       COUNT(*) OVER (PARTITION BY SalesOrder)
FROM Test_Table

回答3:

Try this one

SELECT SaleOrder, [Transaction]
    , Max(Amount) / COUNT([Transaction]) over (partition by SaleOrder)
FROM Test_Table GROUP BY SaleOrder,[Transaction]

来源：https://stackoverflow.com/questions/65441405/divide-by-subquery-returning-subquery-returned-more-than-1-value-error

标签

sql

sql-server

tsql

subquery

division