1、表明 t 列名 a

delete from t where rowid in(

select t.rowid from t,

(

select a,max(rid) rid from

(

select a,rowid rid from t where a in

(select * from t group by(a) having count(a)>1)

) group by a

)t2

where t.a=t2.a and t.rowid != t2.rid

)

fang qiang