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orAClE多列去重

其实思路就是你的过程:1. 首先去重(用distinct) select distinct a,b,c from 表A2. 然后查出a、b列(子查询) select a,b from (select distinct a,b,c from 表A) test或者更简单的(用group by),可以试试,我不确定.select a,bfrom 表Agroup by a,b,c

第一种方式:select distinct x, y from t;第二种方式:select x,y from t group by x,y推荐第二种方式

oracle两表联查重复列如何去除1、过滤重复行 select distinct 字段 from 表明 2、查找重复行 select 字段 ,count(*) from group by 字段 having count(*)>1

select distinct * from tableNamedistinct可以去重

select col1,col2,count(*) from tab_1 group by col1,col2 having count(*) >1; 查出来重复数据了 然后 delete tab_1 a where rowid in ( select max(rowid) from tab_1 b where a.col1=b.col1 and a.col2=b.col2);OK,搞定!记住了,删除之前一定要先备份,在查询是不是要删除的数据,然后再删除.

SELECT A, B, C FROM TABLE_NAME AA WHERE ROWID = (SELECT MIN(ROWID) FROM TABLE_NAME BB WHERE BB.A = AA.A GROUP BY BB.A); 有点混乱,还不如说是某列重复时取第一条数据,你看看这是不是你要的

一般用distinct 关键字去重select distinct * from tabname

单纯是你这样的数据倒是好弄,但你实际不是这样的数据吧. 创建表和插入数据 create table t(日期 int,名称 varchar2(10),种类e799bee5baa6e58685e5aeb931333361303566 varchar2(10),金额 varchar2(10));insert into t values (1,'a','c','g');

1、distinct 关键字的用法:distinct 关键字后面的字段组合去重 distinct 必须select distinct id from test结果 ;根据id 去重select distinct id,name from test2、group by 分组去重select id,name from test group by id,name结果:根据id,name 组合去重3

C列也要考虑对么?delete from table xwhere not exists (select 1 from (select a,b,max(c) c from table group by a,b ) ywhere x.a=y.a and x.b=y.b and x.c=y.c);随机删除重复列:delete from table xwhere exists(select 1 from (select a,b,max(rowid) max_rowid from table group by a,b) ywhere x.a=y.a and x.b=y.b and x.rowid 作业帮用户 2016-12-01 举报

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