Oracle not returning any data for yesterdays hour - sql

Question

I have the following query:
SELECT d_dtm,
BTS_ID,
CASE WHEN D_DTM = (D_DTM-24/24)
THEN sum(V_ATT_CNT)
END AS "LASTATT",
sum(V_ATT_CNT) as "V_ATT_CNT",
CASE WHEN D_DTM = D_DTM
THEN sum(V_ATT_CNT)
END AS "ATT"
FROM DMSN.DS3R_FH_1XRTT_FA_LVL_KPI
WHERE to_date(D_DTM, 'DD/MM/yyyy') >=
(SELECT TO_DATE(max(D_DTM),'DD/MM/YYYY')
FROM DMSN.DS3R_FH_1XRTT_FA_LVL_KPI)-2
GROUP BY d_dtm,
BTS_ID
HAVING CASE WHEN D_DTM = (D_DTM-24/24)
THEN sum(V_ATT_CNT)
END > 0
But it is not returning any results because of the "having" clause. I know it should return results because all I want it to do is in one column have the V_ATT for the current time period, and in the 2nd column, have the V_ATT 24 hours ago. I've checked the data and I should get results back but can't seem to figure out why this is not working...

Answer 1

If you subtotal (group by) D_DTM, you get one row per date. If you want to compare two dates with each other in the same row you need to do one of two things: either a subquery, or a window function like lag/lead.
I think this is what you're looking for:
SELECT d_dtm,
BTS_ID,
lag(sum(V_ATT_CNT), 1) over (partition by bts_id order by d_dtm)
AS "LASTATT",
sum(V_ATT_CNT) as "V_ATT_CNT"
FROM DMSN.DS3R_FH_1XRTT_FA_LVL_KPI
WHERE to_date(D_DTM, 'DD/MM/yyyy') >=
(SELECT TO_DATE(max(D_DTM),'DD/MM/YYYY')
FROM DMSN.DS3R_FH_1XRTT_FA_LVL_KPI)-2
GROUP BY d_dtm,
BTS_ID
Note that the partition by columns in the lag/over is a subset of the group by columns.

Answer 2

I re-wrote the query using a with statement and two queries. Works pretty fast and gives me the correct results.
WITH FRST
AS ( SELECT D_DTM,
BSM_NM,
SUM (V_ATT_CNT) AS "V_ATT_CNT",
SUM (V_CUST_BLK_CNT) AS "V_CUST_BLK_CNT",
SUM (V_DRP_CALL_CNT) AS "V_DRP_CALL_CNT",
SUM (D_ATT_CNT) AS "D_ATT_CNT",
SUM (D_CUST_BLK_CNT) AS "D_CUST_BLK_CNT",
SUM (D_DRP_CALL_CNT) AS "D_DRP_CALL_CNT"
FROM DMSN.DS3R_FH_1XRTT_FA_LVL_KPI
WHERE D_DTM >=
(SELECT MAX (D_DTM) - NUMTODSINTERVAL (12, 'HOUR')
FROM DMSN.DS3R_FH_1XRTT_FA_LVL_KPI)
GROUP BY D_DTM, BSM_NM),
LST
AS ( SELECT D_DTM,
BSM_NM,
SUM (V_ATT_CNT) AS "V_ATT_CNT",
SUM (V_CUST_BLK_CNT) AS "V_CUST_BLK_CNT",
SUM (V_DRP_CALL_CNT) AS "V_DRP_CALL_CNT",
SUM (D_ATT_CNT) AS "D_ATT_CNT",
SUM (D_CUST_BLK_CNT) AS "D_CUST_BLK_CNT",
SUM (D_DRP_CALL_CNT) AS "D_DRP_CALL_CNT"
FROM DMSN.DS3R_FH_1XRTT_FA_LVL_KPI
WHERE D_DTM >=
(SELECT MAX (D_DTM) - NUMTODSINTERVAL (48, 'HOUR')
FROM DMSN.DS3R_FH_1XRTT_FA_LVL_KPI)
GROUP BY D_DTM, BSM_NM),
EVDOLST
AS ( SELECT D_DTM,
BSM_NM,
SUM (ATT_CNT) AS "ATT_CNT",
SUM (CUST_BLK_CNT) AS "CUST_BLK_CNT",
SUM (DRP_CALL_CNT) AS "DRP_CALL_CNT"
FROM DMSN.DS3R_FH_EVDO_FA_LVL_KPI
WHERE D_DTM >=
(SELECT MAX (D_DTM) - NUMTODSINTERVAL (48, 'HOUR')
FROM DMSN.DS3R_FH_EVDO_FA_LVL_KPI)
GROUP BY D_DTM, BSM_NM),
EVDOFRST
AS ( SELECT D_DTM,
BSM_NM,
SUM (ATT_CNT) AS "ATT_CNT",
SUM (CUST_BLK_CNT) AS "CUST_BLK_CNT",
SUM (DRP_CALL_CNT) AS "DRP_CALL_CNT"
FROM DMSN.DS3R_FH_EVDO_FA_LVL_KPI
WHERE D_DTM >=
(SELECT MAX (D_DTM) - NUMTODSINTERVAL (12, 'HOUR')
FROM DMSN.DS3R_FH_EVDO_FA_LVL_KPI)
GROUP BY D_DTM, BSM_NM)
SELECT t1.D_DTM,
t1.BSM_NM,
t2.V_ATT_CNT AS "LASTV_ATTCNT",
t2.V_CUST_BLK_CNT AS "LASTV_BLKCNT",
t2.V_DRP_CALL_CNT AS "LASTV_DRPCNT",
t1.V_ATT_CNT AS "V_ATT_CNT",
t1.V_CUST_BLK_CNT AS "V_CUST_BLK_CNT",
t1.V_DRP_CALL_CNT AS "V_DRP_CALL_CNT",
t2.D_ATT_CNT AS "LASTD_ATTCNT",
t2.D_CUST_BLK_CNT AS "LASTD_BLKCNT",
t2.D_DRP_CALL_CNT AS "LASTD_DRPCNT",
t1.D_ATT_CNT AS "D_ATT_CNT",
t1.D_CUST_BLK_CNT AS "D_CUST_BLK_CNT",
t1.D_DRP_CALL_CNT AS "D_DRP_CALL_CNT",
t3.ATT_CNT AS "EVDO_ATTCNT",
t3.CUST_BLK_CNT AS "EVDO_BLKCNT",
t3.DRP_CALL_CNT AS "EVDO_DRPCNT",
t4.ATT_CNT AS "EVDO_LASTATTCNT",
t4.CUST_BLK_CNT AS "EVDO_LASTBLKCNT",
t4.DRP_CALL_CNT AS "EVDO_LASTDRPCNT"
FROM FRST t1
INNER JOIN LST t2
ON t1.BSM_NM = t2.BSM_NM
AND t1.D_DTM - NUMTODSINTERVAL (24, 'HOUR') = t2.D_DTM
LEFT OUTER JOIN EVDOLST t4
ON t1.BSM_NM = t4.BSM_NM
AND t1.D_DTM - NUMTODSINTERVAL (24, 'HOUR') = t4.D_DTM
LEFT OUTER JOIN EVDOFRST t3
ON t1.BSM_NM = t3.BSM_NM AND t1.D_DTM = t3.D_DTM