如果有name相同的记录 只留下一条，其余的删除。
name的内容不定，相同的记录数不定。
有没有这样的sql语句？
==============================
A:一个完整的解决方案：
将重复的记录记入temp1表:
select [标志字段id],count(*) into temp1 from [表名]
group by [标志字段id]
having count(*)>1
2、将不重复的记录记入temp1表:
insert temp1 select [标志字段id],count(*) from [表名] group by [标志字段id] having count(*)=1
3、作一个包含所有不重复记录的表：
select * into temp2 from [表名] where 标志字段id in(select 标志字段id from temp1)
4、删除重复表:
delete [表名]
5、恢复表：
insert [表名] select * from temp2
6、删除临时表:
drop table temp1
drop table temp2
================================
B:
create table a_dist(id int,name varchar(20))
insert into a_dist values(1,'abc')
insert into a_dist values(1,'abc')
insert into a_dist values(1,'abc')
insert into a_dist values(1,'abc')
exec up_distinct 'a_dist','id'
select * from a_dist
create procedure up_distinct(@t_name varchar(30),@f_key varchar(30))
--f_key表示是分组字段﹐即主键字段
as
begin
declare @max integer,@id varchar(30) ,@sql varchar(7999) ,@type integer
select @sql = 'declare cur_rows cursor for select '+@f_key+' ,count(*) from ' +@t_name +' group by ' +@f_key +' having count(*) > 1'
exec(@sql)
open cur_rows
fetch cur_rows into @id,@max
while @@fetch_status=0
begin
select @max = @max -1
set rowcount @max
select @type = xtype from syscolumns where id=object_id(@t_name) and name=@f_key
if @type=56
select @sql = 'delete from '+@t_name+' where ' + @f_key+' = '+ @id
if @type=167
select @sql = 'delete from '+@t_name+' where ' + @f_key+' = '+''''+ @id +''''
exec(@sql)
fetch cur_rows into @id,@max
end
close cur_rows
deallocate cur_rows
set rowcount 0
end
select * from systypes
select * from syscolumns where id = object_id('a_dist')
* 行列转换--普通
假设有张学生成绩表(CJ)如下
Name Subject Result
张三 语文 80
张三 数学 90
张三 物理 85
李四 语文 85
李四 数学 92
李四 物理 82
想变成
姓名 语文 数学 物理
张三 80 90 85
李四 85 92 82
declare @sql varchar(4000)
set @sql = 'select Name'
select @sql = @sql + ',sum(case Subject when '''+Subject+''' then Result end) ['+Subject+']'
from (select distinct Subject from CJ) as a
select @sql = @sql+' from test group by name'
exec(@sql)
行列转换--合并
有表A,
id pid
1 1
1 2
1 3
2 1
2 2
3 1
如何化成表B:
id pid
1 1,2,3
2 1,2
3 1
创建一个合并的函数
create function fmerg(@id int)
returns varchar(8000)
as
begin
declare @str varchar(8000)set @str=''
select @str=@str+','+cast(pid as varchar) from 表A where id=@id
