去重 数据库_数据库数据怎么去重

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set names utf8;

select catid from supe_categories where name=’金融’;

得出catid;

create table multmp select * from supe_spaceitems where catid in(select catid from supe_categories where name=’金融’); 假设上一句的出的catid为1

／／以下语句是过滤重复

create table tmpa as select itemid from multmp where subject in(select subject from multmp group by subject having count(itemid)>1);

create table tmpb as select min(itemid) as itemid from multmp group by subject having count(itemid)>1;

create table tmptmp as select itemid from multmp where itemid in (select itemid from tmpa ) and itemid not in (select itemid from tmpb);//要删除的数据的itemid

delete from supe_spacenews where itemid in (select itemid from tmptmp);//删除news

delete from multmp where itemid in (select itemid from tmptmp);

drop table tmpa;

drop table tmpb;

drop table tmptmp;

delete from supe_spaceitems where catid in (select catid from supe_categories where name=’金融’); ／／删除原表中 catid为1的数据

insert into supe_spaceitems select * from multmp; ／／将过滤后的数据 添会原表

drop table multmp;／／删除中间表