Having clause not working - sql

Question

i make this query in oracle 11g database
SELECT DISTINCT JOC_FIN_CLTH_DFCT_LOT.LOT_NO,
I.ISSUE_DATE,
R.PROC_DESC,
R.RECV_DATE,
M.DFCT_DATE,
JOC_FIN_CLTH_DFCT_LOT.FCD_MAIN_ID
FROM JOC_FIN_CLTH_DFCT_LOT,
JOC_FIN_CLTH_DFCT_MAIN M,
JOC_DAILY_FABRC_RECV_FOLD R,
JOC_LOT_ISSUE_REG I
WHERE M.FCD_MAIN_ID = JOC_FIN_CLTH_DFCT_LOT.FCD_MAIN_ID
AND R.LOT_NO = JOC_FIN_CLTH_DFCT_LOT.LOT_NO
AND I.LOT_NO = R.LOT_NO
AND I.LOT_YEAR = R.LOT_YEAR
AND JOC_FIN_CLTH_DFCT_LOT.LOT_YEAR = R.LOT_YEAR
AND JOC_FIN_CLTH_DFCT_LOT.LOT_YEAR = '1213'
AND JOC_FIN_CLTH_DFCT_LOT.FCDL_ID IN
( SELECT MIN (DFCT_LOT.FCDL_ID)
FROM JOC_FIN_CLTH_DFCT_LOT DFCT_LOT, JOC_FIN_CLTH_DFCT_MAIN DFT_MAIN
WHERE DFCT_LOT.FCD_MAIN_ID IN (DFT_MAIN.FCD_MAIN_ID)
GROUP BY DFCT_LOT.FCD_MAIN_ID)
ORDER BY JOC_FIN_CLTH_DFCT_LOT.FCD_MAIN_ID
it retrieve data within 2 sec no. of rows=5100
but when i use this query in my front end application it takes too much times so after troubleshooting i find subquery cause problem when data retrieve so i simplify this query
SELECT DISTINCT DFCT_LOT.LOT_NO,
I.ISSUE_DATE,
R.PROC_DESC,
R.RECV_DATE,
M.DFCT_DATE,
DFCT_LOT.FCD_MAIN_ID
FROM JOC_FIN_CLTH_DFCT_LOT DFCT_LOT,
JOC_FIN_CLTH_DFCT_MAIN M,
JOC_DAILY_FABRC_RECV_FOLD R,
JOC_LOT_ISSUE_REG I,
JOC_FIN_CLTH_DFCT_MAIN DFT_MAIN
WHERE M.FCD_MAIN_ID = DFCT_LOT.FCD_MAIN_ID
AND R.LOT_NO = DFCT_LOT.LOT_NO
AND I.LOT_NO = R.LOT_NO
AND I.LOT_YEAR = R.LOT_YEAR
AND DFCT_LOT.LOT_YEAR = R.LOT_YEAR
AND DFCT_LOT.LOT_YEAR = '1213'
AND DFCT_LOT.FCD_MAIN_ID IN (DFT_MAIN.FCD_MAIN_ID)
GROUP BY DFCT_LOT.FCDL_ID,
DFCT_LOT.FCD_MAIN_ID,
DFCT_LOT.LOT_NO,
I.ISSUE_DATE,
R.PROC_DESC,
R.RECV_DATE,
M.DFCT_DATE,
DFCT_LOT.FCD_MAIN_ID
HAVING DFCT_LOT.FCDL_ID in MIN (DFCT_LOT.FCDL_ID)
ORDER BY DFCT_LOT.FCD_MAIN_ID
this is simplified form of above query but number of rows increase
no.of rows=5578 but i know the actual no. of rows=5100
having clause not working here
kindly look into my query and guide me

Answer 1

In your second query you are joining the table JOC_FIN_CLTH_DFCT_MAIN a second time, once as M and once as DFCT_LOT. In the second query's SELECT list you take the first column from M and the last one from DFCT_LOT.
But in the first query they are both from the same M table. When you have more than one record in JOC_FIN_CLTH_DFCT_MAIN for the same FCD_MAIN_ID, then this will result in more combinations in the second query, and this explains why you have more results with it.
But there are several other differences. In the second query you group by many more columns than in the first. Moreover, MIN (DFCT_LOT.FCDL_ID) does not really make sense in the second query, as it is already grouped by, so it is exactly the same as just DFCT_LOT.FCDL_ID. As a consequence, the HAVING clause is just a plain tautology, and you could just as well leave it out and still get the same results.
If you are sure the first query gives the results you want, then I would suggest a different way to achieve a possible optimisation of it:
SELECT DISTINCT
L.LOT_NO,
I.ISSUE_DATE,
R.PROC_DESC,
R.RECV_DATE,
L.DFCT_DATE,
L.FCD_MAIN_ID,
FROM (SELECT L.FCD_MAIN_ID,
L.LOT_NO,
L.LOT_YEAR,
M.DFCT_DATE,
ROW_NUMBER() OVER (PARTITION BY L.FCD_MAIN_ID
ORDER BY L.FCDL_ID) AS RN
FROM JOC_FIN_CLTH_DFCT_LOT L,
INNER JOIN JOC_FIN_CLTH_DFCT_MAIN M
ON M.FCD_MAIN_ID = L.FCD_MAIN_ID
) L
INNER JOIN JOC_DAILY_FABRC_RECV_FOLD R
ON R.LOT_NO = L.LOT_NO
AND R.LOT_YEAR = L.LOT_YEAR
INNER JOIN JOC_LOT_ISSUE_REG I
ON I.LOT_NO = R.LOT_NO
AND I.LOT_YEAR = R.LOT_YEAR
WHERE L.LOT_YEAR = '1213'
AND L.RN = 1
ORDER BY L.FCD_MAIN_ID
Note that I have used the ANSI/ISO syntax for joins, which I would strongly advise you to do. Defining join conditions in the WHERE clause is something of the eighties; don't do it. Queries becomes much more readable once you are used to the ANSI/ISO syntax.
The suggested query selects all the columns that are needed from both JOC_FIN_CLTH_DFCT_LOT and JOC_FIN_CLTH_DFCT_MAIN in the sub-query, that way you don't have to include those tables again.
The major trick is the use of the ROW_NUMBER window function, which gives an sequence number according to the PARTITION clause. The outer query then filters for only those records which got number 1, which are the records where the value of FCD_MAIN_ID is minimal for a given FCDL_ID.