Delete Rows brought back from a Select statement that contains a having and group by clause in Oracle

Question

I have this select statement:

SELECT d.idcprefix,
         d.orgdept,
         d.idcseq,
         d.subcont, 
         d.actualcomp, 
         COUNT (*) AS "No Duplicates"
    FROM DCS_IDC, DCS_IDC z
   WHERE     D.IDCPREFIX = z.idcprefix
         AND z.orgdept = d.orgdept
         AND z.idcseq = d.idcseq
         and D.SUBCONT is not null
  HAVING COUNT (*) > 1
GROUP BY d.idcprefix,
         d.orgdept,
         d.idcseq,
         d.subcont,
         d.actualcomp
ORDER BY d.idcprefix,
         d.orgdept,
         d.idcseq,
         d.subcont,
         d.actualcomp

and I want to delete the rows that are brought back from this statement, any ideas?

A Delete FROM gives me a ORA-01732: data manipulation operation not legal on this view error because, I believe, I am comparing two tables albeit the same table.

I also tried a delete from tablename where rows exist, but that deleted far more rows than I wanted.

The "duplicates" are based on Subcont. There were records inserted into the database / application using the subcont field, which was meant to be blank, so now I have records which are the same except for one has, for example, A in subcont and it's blank in the other:

idcprefix, subcont, orgdept and idcseq
1          A        ABC         1
1                   ABC         1
2          A        BCD         1
2                   BCD         1

The query shows all the records that have a subcont that are dupliates of the ones that don't and I need to remove the ones with the subcont value.

Help would be much appreciated!

Answer 1

Assuming that (idcprefix, subcont, orgdept, idcseq) is unique, how about the below?

DELETE FROM DCS_IDC
WHERE (idcprefix, subcont, orgdept, idcseq) IN (
  WITH del AS (
  SELECT d.idcprefix,
     d.orgdept,
     d.idcseq,
     d.subcont, 
     d.actualcomp, 
     COUNT (*) AS "No Duplicates"
  FROM DCS_IDC, DCS_IDC z
  WHERE     D.IDCPREFIX = z.idcprefix
     AND z.orgdept = d.orgdept
     AND z.idcseq = d.idcseq
     and D.SUBCONT is not null
  HAVING COUNT (*) > 1
  GROUP BY d.idcprefix,
     d.orgdept,
     d.idcseq,
     d.subcont,
     d.actualcomp
  ORDER BY d.idcprefix,
     d.orgdept,
     d.idcseq,
     d.subcont,
     d.actualcomp
  )
 SELECT idcprefix, subcont, orgdept, idcseq FROM del
)

Answer 2

How about:

BEGIN
  FOR aRow IN (SELECT d.idcprefix,
                      d.orgdept,
                      d.idcseq,
                      COUNT(*) AS DUP_COUNT
                 FROM DCS_IDC d
                 HAVING COUNT(*) > 1
                 GROUP BY d.idcprefix,
                          d.orgdept,
                          d.idcseq)
  LOOP
    DELETE FROM DCS_IDC
      WHERE IDCPREFIX = aRow.IDCPREFIX AND
            ORGDEPT = aRow.ORGDEPT AND
            IDCSEQ = aRow.IDCSEQ AND
            SUBCONT IS NOT NULL;
  END LOOP;
END;

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