Query returning zero results for yesterdays same hour

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...
Edited by: k1ng87 on Apr 22, 2013 1:03 PM

Answer 1

Hi,
k1ng87 wrote:
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",
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But it is not returning any results because of the "having" clause. You're right:HAVING CASE
     WHEN d_dtm = (d_dtm - 24/24)
     THEN SUM (v_att_cnt)
     END > 0
Whatever d_dtm is, it's not d_dtm - 24/24, so the WHEN condition will never be TRUE.  That means the CASE expression will always return NULL, and NULL is not greater than 0, so the HAVING condition will never be TRUE.
k1ng87 wrote:
confused on what I'm missing here...I'm using version 11g, not sure if that matters for this ? though....There is no version 11f or 11h, so it's kind of silly to say you're using 11g.  Why not give your actual version number, like 11.2.0.2.0?  Sometimes, the part after 11 makes a huge difference.
But probably not in this case, as you said.   What's more important is for you to post CREATE TABLE and INSERT statements for a little sample data, and the results you want from that sample data.
No kidding; see the forum FAQ {message:id=9360002}.