蚂蚁的:去除重复值如果有ID字段,就是具有唯一性的字段delect table where id not in ( select max(id) from table group by col1,col2,col3... ) group by 子句后跟的字段就是你用来判断重复的条件,如只有col1,那么只要col1字段内容相同即表示记录相同。2,如果是判断所有字段也可以这样 select * into #aa from table group by id1,id2,.... delete table insert into table select * from #aa3,没有ID的情况select identity(int,1,1) as id,* into #temp from tabel delect # where id not in ( select max(id) from # group by col1,col2,col3...) delect table inset into table(...) select ..... from #temp col1+','+col2+','...col5 联合主键 select * from table where col1+','+col2+','...col5 in ( select max(col1+','+col2+','...col5) from table where having count(*)>1 group by col1,col2,col3,col4 ) group by 子句后跟的字段就是你用来判断重复的条件,如只有col1,那么只要col1字段内容相同即表示记录相同。2, select identity(int,1,1) as id,* into #temp from tabel select * from #temp where id in ( select max(id) from #emp where having count(*)>1 group by col1,col2,col3...)
alter table 表 add newfield int identity(1,1)delete 表 where newfield not in( select min(newfield) from 表 group by 除newfield外的所有字段 )alter table 表 drop column newfield或:select distinct * into #temp from 表 truncate table 表 insert 表 select * from #temp drop table #temp
大力的回答,我觉得比较适合你这个表 删除重复的,只留一条:alter table 表 add newfield int identity(1,1)delete 表 where newfield not in( select min(newfield) from 表 group by 除newfield外的所有字段 )alter table 表 drop column newfield
select distinct * into #temp from tableNametruncate table tableNameinsert into tableName select * from #tempdrop table #temp
删除重复数据一、具有主键的情况 a.具有唯一性的字段id(为唯一主键) delect table where id not in ( select max(id) from table group by col1,col2,col3... ) group by 子句后跟的字段就是你用来判断重复的条件,如只有col1, 那么只要col1字段内容相同即表示记录相同。b.具有联合主键 假设col1+','+col2+','...col5 为联合主键 select * from table where col1+','+col2+','...col5 in ( select max(col1+','+col2+','...col5) from table group by col1,col2,col3,col4 having count(*)>1 ) group by 子句后跟的字段就是你用来判断重复的条件, 如只有col1,那么只要col1字段内容相同即表示记录相同。 or select * from table where exists (select 1 from table x where table.col1 = x.col1 and table.col2= x.col2 group by x.col1,x.col2 having count(*) >1)c:判断所有的字段 select * into #aa from table group by id1,id2,.... delete table insert into table select * from #aa二、没有主键的情况a:用临时表实现 select identity(int,1,1) as id,* into #temp from ta delect #temp where id not in ( select max(id) from # group by col1,col2,col3... ) delete table ta inset into ta(...) select ..... from #tempb:用改变表结构(加一个唯一字段)来实现 alter table 表 add newfield int identity(1,1) delete 表 where newfield not in ( select min(newfield) from 表 group by 除newfield外的所有字段 )alter table 表 drop column newfield
)
group by 子句后跟的字段就是你用来判断重复的条件,如只有col1,那么只要col1字段内容相同即表示记录相同。2,如果是判断所有字段也可以这样
select * into #aa from table group by id1,id2,....
delete table
insert into table
select * from #aa3,没有ID的情况select identity(int,1,1) as id,* into #temp from tabel
delect # where id not in (
select max(id) from # group by col1,col2,col3...)
delect table
inset into table(...)
select ..... from #temp
col1+','+col2+','...col5 联合主键
select * from table where col1+','+col2+','...col5 in ( select max(col1+','+col2+','...col5) from table
where having count(*)>1
group by col1,col2,col3,col4
)
group by 子句后跟的字段就是你用来判断重复的条件,如只有col1,那么只要col1字段内容相同即表示记录相同。2,
select identity(int,1,1) as id,* into #temp from tabel
select * from #temp where id in (
select max(id) from #emp where having count(*)>1 group by col1,col2,col3...)
where newfield not in(
select min(newfield) from 表 group by 除newfield外的所有字段
)alter table 表 drop column newfield或:select distinct * into #temp from 表
truncate table 表
insert 表 select * from #temp
drop table #temp
删除重复的,只留一条:alter table 表 add newfield int identity(1,1)delete 表
where newfield not in(
select min(newfield) from 表 group by 除newfield外的所有字段
)alter table 表 drop column newfield
删除重复数据一、具有主键的情况
a.具有唯一性的字段id(为唯一主键)
delect table
where id not in
(
select max(id) from table group by col1,col2,col3...
)
group by 子句后跟的字段就是你用来判断重复的条件,如只有col1,
那么只要col1字段内容相同即表示记录相同。b.具有联合主键
假设col1+','+col2+','...col5 为联合主键
select * from table where col1+','+col2+','...col5 in (
select max(col1+','+col2+','...col5) from table
group by col1,col2,col3,col4
having count(*)>1
)
group by 子句后跟的字段就是你用来判断重复的条件,
如只有col1,那么只要col1字段内容相同即表示记录相同。
or
select * from table where exists (select 1 from table x where table.col1 = x.col1 and
table.col2= x.col2 group by x.col1,x.col2 having count(*) >1)c:判断所有的字段
select * into #aa from table group by id1,id2,....
delete table
insert into table
select * from #aa二、没有主键的情况a:用临时表实现
select identity(int,1,1) as id,* into #temp from ta
delect #temp
where id not in
(
select max(id) from # group by col1,col2,col3...
)
delete table ta
inset into ta(...)
select ..... from #tempb:用改变表结构(加一个唯一字段)来实现
alter table 表 add newfield int identity(1,1)
delete 表
where newfield not in
(
select min(newfield) from 表 group by 除newfield外的所有字段
)alter table 表 drop column newfield