GROUP BY USING CASE ?

Question

SELECT
E.ACTV_DESC AS ACTV_DESC,
E.ACTV_CDE AS ACTV_CDE,
COUNT(E.ACTV_CDE) AS CNT_ACTV_CDE,
CASE WHEN B.VET_OTHR_ELIG_CDE ='01' THEN 'NO' ELSE NULL END AS VET_NO, -- new column to be added
CASE WHEN B.VET_OTHR_ELIG_CDE IN ('02','03','04') THEN 'YES' ELSE NULL END AS VET_YES --new column to be added
FROM
ETR_RGT_PARTC A,
ETR_INT_PARTC_INTK_JS B,
ETR_SDT_PARTC_PGM_ACTV C,
ETR_VM_SM_STFFNME D,
ETR_SMT_ACTV_MSTR E
WHERE
A.PARTC_ID = B.PARTC_ID AND
B.PARTC_ID = C.PARTC_ID AND
B.APPLC_ID = C.APPLC_ID AND
B.PGM_ID = C.PGM_ID AND
C.RESP_STFF_ID = D.STFF_ID AND
C.PGM_ID = E.PGM_ID AND
C.ACTV_ID = E.ACTV_ID AND
(D.RACF_ID LIKE :P_RACF_ID||'%') AND
C.LOC_ID LIKE 'ES%' AND
(TRUNC(C.CRTE_DTE) >= :P_FROM_DATE AND
TRUNC(C.CRTE_DTE) <=:P_TO_DATE) AND
D.STFF_LOC_ID = 'ES00'||:P_LOCL_OFFC_ID
AND D.CLOS_DTE IS NULL
GROUP BY
ACTV_DESC,
ACTV_CDE
ORDER BY ACTV_CDE;
we cant group by using alias in this situation what shud i do ?
Thanks in advance

Answer 1

If you want to group by using the added new columns as well, then all you need to do is - put the full CASE statements into group by clause without alias.
But if you do not want to group by your data based on the added new columns then you can use the inline view and do the group by first based on first 2 columns and then do the CASE afterwards.
Also, one error I noticed in the give query is that you are doing COUNT on the column E.ACTV_CDE which is also your group by column - E.ACTV_CDE. This means that you will always receive 1 as count for each actv_cde as you are doing the grouping on the same column.