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delete table where rowid not in (select max(rowid) from table group by col1,col2,...,coln);

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¶Ô£¬ÓÃrowid À´¹ýÂË.

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delete tb a
where a.rowid > (select min(b.rowid)
from tb b
where b.xx = a.xx)

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delete ±íÃû where rowid not in (select max(rowid) from ±íÃû group by ÁÐÃû);£¨×¢ÕâÀïµÄÁÐÃû¾ÍÊÇÄã¸ù¾ÝÄǸöÁÐÅжÏÖظ´µÄ£¬¿ÉÒÔΪ¶àÁУ©

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delete from table where rowid in (select a.rowid from table a, table b  
where a.rowid>b.rowid and a.col1=b.col1 and a.col2 = b.col2 and ...)

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ʹÓÃrowidʱ×îºóµÄ½â¾ö°ì·¨,±íÖÐÿÐмǼµÄrowid¶¼ÊÇΨһµÄ
delete from table_A a
  where a.rowid < (select max(b.rowid) 
  from table_A b 
  where a.column1 = b.column1
  and a.column2 = b.column2
  ... --ÓжàÉÙÁоÍд¶àÉÙÁУ¬·½·¨Í¬ÉÏ
  );

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