???????????????????????????е??????????????????????????????????????????????????????????????????????????????????????????????????Щ?????????????????????????????е???п????

????????????????????? ????????rowid??????????????????????????????????????????????????????

??????????? ??test???У???????col1??col2??col3;????????????к???????????????????????????Щ????????????????????????????μ???????????????

??????????????

????Delete from test where rowid not in(select  max(rowid) from test group by col1??col2??col3);(???ü?)

??????????????

????Delete form test where (col1??col2??col3) in(select col1??col2??col3 from test  group bycol1??col2??col3) and rowid not in(select max(rowid) from test group by col1??col2??col3)(??????????????????????????)

???????????????????????д???????????

???????????????

????Delete from test a where a.rowid  !=(select  max(rowid) from test b where a.col1=b.col1and a.col2=b.col2  and  a.col3=b.col3)

???????Σ?

????Delete from test a where a.rowid<(select  max(rowid) from test b where a.col1=b.col1 and a.col2=b.col2  and  a.col3=b.col3)

??????????????????????????????????

?????????????????????????

????Create table test2 as select distinct * from test;(?????????????д?????????)

????Truncate table test;(?????????)

????Insert into test  select * from test2;?????2???????????

??????????????????鷳???????????????????????????

????????rowid????????????????е??????

???????????????????????????е???????????rowid?????б?????У??????????????????rowid ????????????