SQL Group by problem

[tanvirtonu]

Why cant I execute the following query in MsAccess-

SELECT SalesInvoice.ID, SalesInvoice.CustomerID, SalesInvoice.Commission, Sum(SalesInvoice.TotalAmount) AS SumOfTotalAmount
FROM SalesInvoice
GROUP BY SalesInvoice.CustomerID;

It says " you tried to execute a query that doesn't include the specified expresiion "ID" as part of an aggregate function "

But I can execute this-

SELECT CustomerID, Sum(TotalAmount) AS SumOfTotalAmount
FROM SalesInvoice
GROUP BY CustomerID;

Can't I select multiple columns in aggregation? PLs help me.

 

[pbaldy]

In a totals query, each field in the SELECT clause must either be aggregated in some way (Sum, Max, etc) or be included in the GROUP BY clause. You'll have to do one or the other to both ID and Commission.