T-SQL GROUP BY ISSUE WITH CASE STATEMENT - sql-server

Question

I have a query with a CASE statement and I need to do a GROUP BY on the alias. I understand that cannot be done so I tried to use a subquery, but it is not working.
Here is the query that I was working on:
SELECT
a.Vendor,
a.Month_Sold
--SUM(sd.SBQSHP) AS Sales_Qty,
--SUM(sd.SBEPRC) AS Sales_Dlr
FROM
(SELECT
sd.IFPRVN AS Vendor,
vn.ACNAME AS Vendor_Name,
CASE
WHEN sd.SBINDT BETWEEN '2012-07-30' AND '2012-08-26' THEN 'August 2012'
WHEN sd.SBINDT BETWEEN '2012-08-27' AND '2012-09-30' THEN 'September 2012'
WHEN sd.SBINDT BETWEEN '2012-10-01' AND '2012-10-28' THEN 'October 2012'
WHEN sd.SBINDT BETWEEN '2012-10-29' AND '2012-11-25' THEN 'November 2012'
WHEN sd.SBINDT BETWEEN '2012-11-26' AND '2012-12-31' THEN 'December 2012'
WHEN sd.SBINDT BETWEEN '2013-01-01' AND '2013-01-27' THEN 'January 2013'
WHEN sd.SBINDT BETWEEN '2013-01-28' AND '2013-02-24' THEN 'Febuary 2013'
WHEN sd.SBINDT BETWEEN '2013-02-25' AND '2013-03-31' THEN 'March 2013'
END AS Month_Sold
FROM
dbo.SalesData sd
INNER JOIN dbo.S2K_VEND vn ON vn.ACVEND = sd.IFPRVN
WHERE
sd.SBINDT > '2012-07-29'
AND
sd.SBCLS IN ('1500')
AND
sd.SBDIV NOT IN ('4000')
)a
GROUP BY
a.Vendor,
a.Month_Sold
ORDER BY
a.Vendor,
a.Month_Sold
The two columns that are commented out need to be included somehow. Any suggestions?

Answer 1

Really, putting pretty labels on your date output should be a job for the presentation tier. FORMAT() in C# etc. is pretty powerful. Barring that, don't convert to pretty string labels until the last possible point, which will require one more layer:
SELECT
Vendor,
DATENAME(MONTH, Month_Sold) + ' ' + RTRIM(YEAR(Month_Sold)),
Sales_Qty,
Sales_Dlr
FROM
(
SELECT
Vendor,
Month_Sold,
SUM(SBQSHP) AS Sales_Qty,
SUM(SBEPRC) AS Sales_Dlr
FROM
(
SELECT
sd.IFPRVN AS Vendor,
vn.ACNAME AS Vendor_Name, -- why is this here?
CASE
WHEN sd.SBINDT BETWEEN '2012-07-30' AND '2012-08-26' THEN '2012-08-01'
WHEN sd.SBINDT BETWEEN '2012-08-27' AND '2012-09-30' THEN '2012-09-01'
...
WHEN sd.SBINDT BETWEEN '2013-01-28' AND '2013-02-24' THEN '2013-02-01'
WHEN sd.SBINDT BETWEEN '2013-02-25' AND '2013-03-31' THEN '2013-03-01'
END AS Month_Sold
FROM dbo.SalesData sd
INNER JOIN dbo.S2K_VEND vn
ON vn.ACVEND = sd.IFPRVN
WHERE sd.SBINDT > '2012-07-29'
AND sd.SBCLS IN ('1500')
AND sd.SBDIV NOT IN ('4000')
) AS a
GROUP BY Vendor, Month_Sold
) AS b
ORDER BY
Vendor,
Month_Sold;

Answer 2

Simply select the values you need to aggregate in your subquery with alias "a"
Add to subquery "a" select statement:
SELECT
sd.IFPRVN AS Vendor,
vn.ACNAME AS Vendor_Name,
sd.SBQSHP,
sd.SBEPRC
CASE
...
Uncomment SUM statements at top level select statement but change alias from "sd" to "a"
SUM(a.SBQSHP) AS Sales_Qty,
SUM(a.SBEPRC) AS Sales_Dlr