mySQL: Remove Duplicates - remove duplicates in one pass at the table

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Snippet Name: Remove Duplicates

Description: remove duplicates in one pass at the table

Comment: First, you need to decide which fields constitute a duplicate, list these in each of the two 'group by' clauses, replacing fld1, fld2, etc.

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Highlight Mode: PLSQL
Last Modified: February 28th, 2009

DELETE FROM tablename
WHERE ROWID IN (
   SELECT ROWID
   FROM test
   GROUP BY ROWID, fld1, fld2, fld3
   MINUS
   SELECT MIN(ROWID)
   FROM test
   GROUP BY fld1, fld2, fld3);