方式一
DELETE FROM TABLENAME T
WHERE T.ROWID NOT IN(
SELECT MAX(B.ROWID) FROM TABLENAME B
GROUP BY B.COL1, B.COL2 ...
)
方式二
DELETE FROM TABLENAME T
WHERE T.ROWID <> (
SELECT MAX(B.ROWID) FROM TABLENAME B
WHERE T.COL1 = B.COL1
AND T.COL2 = B.COL2
)
方式二效率明显高于方式一
