SQL column as select statement to be referenced into a group by

Question

Is there a notation or solution to be able to reference a column that is a inline select statement within a group by as detailed below? The group by will not accept the alias. I also tried to make the SQL a MAX to remove the need for the group by reference and this returned invalid expression.
SELECT DISTINCT hdr.BUSINESS_UNIT,
hdr.SESSN_ID,
hdr.STREAM_ROOT_ID,
hdr.SESSN_STS_CD,
hdr.SESSN_CRE_DTTM,
CASE
WHEN C.OPRID <> ' ' THEN C.OPRID
ELSE S.OPERATOR
END OPRID,
strm.QS_APP_CONTEXT,
RECV.QTY_SH_RECVD Quantity_Received,
CASE
WHEN hdr.BUSINESS_UNIT = 'MFG01' THEN MAX(G.MFDS_SGRP_SIZE)
ELSE MAX(S.SESSN_SGRP_SIZE)
END Quantity_Inspected,
MAX(S.QS_VALUEREADING_1) Defect_Count,
CASE
WHEN MAX(S.QS_VALUEREADING_1) = 0 THEN ' '
ELSE MAX(G.MFDS_NAME)
END Characteristic,
MAX(CMNT.QS_COMMENT2) COMMENTS,
strm.INV_ITEM_ID,
itm.DESCR,
strm.WORK_CENTER_CODE,
strm.VENDOR_ID,
*(SELECT V.NAME1 FROM PS_VENDOR V WHERE strm.VENDOR_ID = V.VENDOR_ID AND V.SETID = (SELECT SETID FROM PS_SET_CNTRL_REC*
WHERE  RECNAME = 'VENDOR'
AND SETCNTRLVALUE = strm.BUSINESS_UNIT)) VENDOR_NAME,
strm.PRDN_AREA_CODE,
strm.COMPL_OP_SEQ,
strm.PRODUCTION_TYPE,
C.RECEIVER_ID,
C.RECV_LN_NBR,
RECV.PO_ID,
RECV.LINE_NBR,
RECV.SCHED_NBR,
C.PRODUCTION_ID,
C.SERIAL_ID,
C.INV_LOT_ID
FROM PS_QS_SESSN_HDR8 hdr
LEFT OUTER JOIN PS_QS_SESSN_TRACE8 C
ON hdr.BUSINESS_UNIT = C.BUSINESS_UNIT
AND hdr.SESSN_ID = C.SESSN_ID
LEFT OUTER JOIN PS_RECV_INSPDTL_VW RECV
ON C.BUSINESS_UNIT = RECV.BUSINESS_UNIT
AND C.RECEIVER_ID = RECV.RECEIVER_ID
AND C.RECV_LN_NBR = RECV.RECV_LN_NBR
LEFT OUTER JOIN PS_QS_STREAM_ROOT strm
ON hdr.STREAM_ROOT_ID = strm.STREAM_ROOT_ID
AND hdr.BUSINESS_UNIT = strm.BUSINESS_UNIT
LEFT OUTER JOIN PS_QS_STREAM8_VW G
ON strm.STREAM_ROOT_ID = G.STREAM_ROOT_ID
AND strm.BUSINESS_UNIT = G.BUSINESS_UNIT
LEFT OUTER JOIN PS_QS_SUBGROUP S
ON hdr.BUSINESS_UNIT = S.BUSINESS_UNIT
AND hdr.SESSN_ID = S.SESSN_ID
AND S.STREAM_ID = G.STREAM_ID
LEFT OUTER JOIN PS_QS_SESSN_COMM8 CMNT
ON S.BUSINESS_UNIT = CMNT.BUSINESS_UNIT
AND S.SESSN_ID = CMNT.SESSN_ID
AND S.STREAM_ID = CMNT.STREAM_ID
AND C.SAMPLE = CMNT.SAMPLE
LEFT OUTER JOIN PS_MASTER_ITEM_TBL itm
ON itm.INV_ITEM_ID = strm.INV_ITEM_ID
LEFT OUTER JOIN PS_SET_CNTRL_REC cntrl
ON itm.SETID = cntrl.SETID
AND cntrl.RECNAME = 'MASTER_ITEM_TBL'
AND cntrl.SETCNTRLVALUE = strm.BUSINESS_UNIT
WHERE S.QS_VALUEREADING_1 = (SELECT MAX(S2.QS_VALUEREADING_1)
FROM PS_QS_SUBGROUP S2
WHERE S2.BUSINESS_UNIT = S.BUSINESS_UNIT
AND S2.SESSN_ID = S.SESSN_ID
AND S2.STREAM_ID = S.STREAM_ID)
GROUP BY hdr.BUSINESS_UNIT,
hdr.SESSN_ID,
hdr.STREAM_ROOT_ID,
hdr.SESSN_STS_CD,
hdr.SESSN_CRE_DTTM,
C.OPRID,
S.OPERATOR,
strm.QS_APP_CONTEXT,
RECV.QTY_SH_RECVD,
strm.INV_ITEM_ID,
itm.DESCR,
strm.WORK_CENTER_CODE,
strm.VENDOR_ID,
VENDOR_NAME,
strm.PRDN_AREA_CODE,
strm.COMPL_OP_SEQ,
strm.PRODUCTION_TYPE,
C.RECEIVER_ID,
C.RECV_LN_NBR,
RECV.PO_ID,
RECV.LINE_NBR,
RECV.SCHED_NBR,
C.PRODUCTION_ID,
C.SERIAL_ID,
C.INV_LOT_ID

Answer 1

Hi,
Assign the alias in a sub-query. Then you'll be able to use it wherever you want to, and how many times you want to, in a super-query.
For example:
WITH     got_vendor     AS
     SELECT     hdr.business_unit
              SELECT  v.name1
              FROM    ps_vendor     v
              WHERE   strm.vendor_id     = v.vendor_id
              AND     v.setid          = (
                                            SELECT  setid
                                    FROM    ps_set_cntrl_rec
                                    WHERE   recname          = 'VENDOR'
                                    AND     setcntrlvalue      = strm.business_unit
          )           AS vendor_name
     FROM      ps_qs_sessn_hdr8     hdr
SELECT       business_unit          -- NOTE: no hdr.; all columns are from got_vendor now
,       vendor
FROM       got_vendor
GROUP BY  business_unit
,       vendor
;When you define an alias (such as vendor) in a query, you can use that alias in the ORDER BY clause of that same query, but that's the only place in that same query where you can use it. If you want to use the alias anywhere else (e.g., in the GROUP BY clause, as in your example, the WHERE clause, or elsewhere in the SELECT clause), then you probably want to compute it in a sub-query, as shown above.
There's probably a better way to compute vendor, but that's a separate problem.
Edited by: Frank Kulash on Jan 3, 2012 10:37 AM
Added example