create table lease_stage(leaseid varchar(100),stage varchar(100))
go
insert into lease_stage
select 1000, 10 union all
select 1000, 20 union all
select 1000, 30 union all
select 1001, 10 union all
select 1001, 20
go
--写一个聚合函数:
create function dbo.fn_Merge(@f varchar(100))
returns varchar(8000)
as
begin
declare @r varchar(8000)
set @r=''
select @r=@r+ '|' + stage from lease_stage where leaseid=@f
return stuff(@r,1,1,'')
end
go-- 调用函数
select leaseid, dbo.fn_Merge(leaseid) as leaseid from lease_stage group by leaseidgo
drop table lease_stage
drop function fn_Merge
go
insert into lease_stage
select 1000, 10 union all
select 1000, 20 union all
select 1000, 30 union all
select 1001, 10 union all
select 1001, 20
go
--写一个聚合函数:
create function dbo.fn_Merge(@f varchar(100))
returns varchar(8000)
as
begin
declare @r varchar(8000)
set @r=''
select @r=@r+ '|' + stage from lease_stage where leaseid=@f
return stuff(@r,1,1,'')
end
go-- 调用函数
select leaseid, dbo.fn_Merge(leaseid) as leaseid from lease_stage group by leaseidgo
drop table lease_stage
drop function fn_Merge
go
insert into lease_stage
select 1000, 10 union all
select 1000, 20 union all
select 1000, 30 union all
select 1001, 10 union all
select 1001, 20
go
--写一个聚合函数:
create function dbo.fn_Merge(@f varchar(100))
returns varchar(8000)
as
begin
declare @r varchar(8000)
set @r=''
select @r=@r+ '|' + stage from lease_stage where leaseid=@f
return stuff(@r,1,1,'')
end
go-- 调用函数
select leaseid, dbo.fn_Merge(leaseid) as stage from lease_stage group by leaseidgo
drop table lease_stage
drop function fn_Merge
/*leaseid stage
-----------------------
1000 10|20|30
1001 10|20
*/
insert lease_stage select 1000, 10
insert lease_stage select 1000, 20
insert lease_stage select 1000, 30
insert lease_stage select 1001, 10
insert lease_stage select 1001, 20--drop table lease_stagecreate function test_f(@leaseid int)
returns varchar(200)
as
begin
declare @s varchar(200)
select @s=isnull(@s+'|','')+rtrim(stage)
from lease_stage where leaseid=@leaseid
return @s
endselect distinct leaseid,[stage]=dbo.test_f(leaseid) from lease_stageleaseid stage
----------- --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1000 10|20|30
1001 10|20(所影响的行数为 2 行)
select leaseid, dbo.fn_Merge(leaseid) as stage
from lease_stage
group by leaseid
/*leaseid stage
-----------------------
1000 10|20|30
1001 10|20
*/
declare @lease_stage table (leaseid int, stage int)
insert @lease_stage select 1000, 10
insert @lease_stage select 1000, 20
insert @lease_stage select 1000, 30
insert @lease_stage select 1001, 10
insert @lease_stage select 1001, 20SELECT *
FROM(SELECT DISTINCT leaseid
FROM @lease_stage)A
OUTER APPLY(SELECT [values]= STUFF(REPLACE(REPLACE(
(SELECT stage FROM @lease_stage N WHERE leaseid = A.leaseid
FOR XML AUTO ), '<N stage="', '|'), '"/>', ''), 1, 1, ''))N
(1 行受影响)
leaseid values
----------- ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1000 10|20|30
1001 10|20(2 行受影响)
1 :普通SQL语句可以用Exec执行
eg: Select * from tableName
Exec('select * from tableName')
Exec sp_executesql N'select * from tableName' -- 请注意字符串前一定要加N
2:字段名,表名,数据库名之类作为变量时,必须用动态SQL
eg:
declare @fname varchar(20)
set @fname = 'FiledName'
Select @fname from tableName -- 错误,不会提示错误,但结果为固定值FiledName,并非所要。
Exec('select ' + @fname + ' from tableName') -- 请注意 加号前后的 单引号的边上加空格
当然将字符串改成变量的形式也可
declare @fname varchar(20)
set @fname = 'FiledName' --设置字段名
declare @s varchar(1000)
set @s = 'select ' + @fname + ' from tableName'
Exec(@s) -- 成功
exec sp_executesql @s -- 此句会报错
declare @s Nvarchar(1000) -- 注意此处改为nvarchar(1000)
set @s = 'select ' + @fname + ' from tableName'
Exec(@s) -- 成功
exec sp_executesql @s -- 此句正确
3. 输出参数
declare @num int,
@sqls nvarchar(4000)
set @sqls='select count(*) from tableName'
exec(@sqls)
--如何将exec执行结果放入变量中?
declare @num int,
@sqls nvarchar(4000)
set @sqls='select @a=count(*) from tableName '
exec sp_executesql @sqls,N'@a int output',@num output
select @num