I get the error . . . You tried to execute a query that does not include the specified expression "SellName" as part of an aggregate function.
I can't figure it out in this example.

The third set of Sum(iif . . . produces incorect results.

What am I missing here?

Thanks, Rick . . .

SELECT Scmls.ListName, Scmls.SellName, Scmls.SalePrice,

Sum(IIf(Scmls.ListName And Scmls.SellName Like Scmls.ListName,1,0))*2 AS WSO,
Sum(IIf(Scmls.ListName And Scmls.SellName Like Scmls.ListName,Scmls.SalePrice,0))*2 AS WSODV,

Sum(iif(Scmls.ListName <> Scmls.SellName,1,0)) AS TSO,
Sum(iif(Scmls.ListName <> Scmls.SellName,Scmls.SalePrice,0)) AS TSODV,

Sum(iif(Scmls.SellName <> Scmls.ListName,1,0)) AS WST,
Sum(iif(Scmls.SellName <> Scmls.ListName,Scmls.SalePrice,0)) AS WSTDV,

WSO+TSO+WST AS [Total Transactions],
Sum(IIf(Scmls.ListName,Scmls.SalePrice,0)) AS[Listing Dollar Volume],
WSODV+TSODV+WSTDV AS[Listing and Sales Dollar Volume]

FROM Scmls
GROUP BY Scmls.ListName
ORDER BY 10 DESC;

Your Group By statement should include all the fields that are not SUMMED in your SELECT statement. Right now you have 3 in the select, but only one in the group by.

Thanks RedNeckGeek

I made that correction but now the second and third set of
Sum(iif( . . . statements fail to calculate at all.

I'm not understanding the relationships between the GROUP BY, ORDER BY and HAVING scenarios, and how they effect the Sum(iif( . . . statements.

What show I be looking for here?

Thanks again . . . Rick

In the first "set", what is this supposed to be evaluating?

Scmls.ListName And Scmls.SellName Like Scmls.ListName

That looks strange, but it may just be something I've never tried before...