Question

I have the following SQL query

SELECT
   [Date], 
   DATENAME(dw,[Date]) AS Day, 
   SUM(CASE WHEN ChargeCode IN (SELECT ChargeCode FROM tblChargeCodes WHERE Chargeable = 1) THEN Units ELSE 0 END) ChargeableTotal,
   SUM(CASE WHEN ChargeCode IN (SELECT ChargeCode FROM tblChargeCodes WHERE Chargeable = 0) THEN Units ELSE 0 END) NotChargeableTotal,
   SUM(Units) AS TotalUnits
FROM 
   tblTimesheetEntries 
WHERE 
   UserID = 'PJW' 
   AND Date >= '2013-01-01' 
GROUP BY 
   [Date] 
ORDER BY 
   [Date] DESC;

But I get the error message:

Cannot perform an aggregate function on an expression containing an aggregate or a subquery.

Because I am using sub queries in the Case Else Summation.

How can I revise my query to get 2 x Sums of [Units] one for Chargeable = true, and one for Chargeable = false, even though the Chargeable field is in a different table to all the other information. The two tables are linked by ChargeCode which appears in both tblTimesheetEntries and tblChargeCodes.

Answer 1

Have you tried joining the tables on the chargeCode:

SELECT e.[Date], 
  DATENAME(dw,e.[Date]) AS Day, 
  SUM(CASE WHEN c.Chargeable = 1 THEN e.Units ELSE 0 END) ChargeableTotal,
  SUM(CASE WHEN c.Chargeable = 0 THEN e.Units ELSE 0 END) NotChargeableTotal,
  SUM(e.Units) AS TotalUnits
FROM tblTimesheetEntries e
LEFT JOIN tblChargeCodes c
  on e.ChargeCode = c.ChargeCode
WHERE e.UserID = 'PJW' 
  AND e.Date >= '2013-01-01' 
GROUP BY e.[Date] 
ORDER BY e.[Date] DESC;