CREATE PROCEDURE [dbo].[Select_data]
@report_id int output
AS
declare @new_string varchar(8000) --变量要加@
declare @Select_str varchar(8000)
declare @from_str varchar(8000)select @select_str=[select],@from_str=[from] --这里原来少个逗号
from server_name.db_name.表A where report_id=@report_iddeclare @temp_str nvarchar(4000)
select replace (@select_str,'','''')
select @temp_str=N'select @new_str='+@select_str+@from_strexec sp_executesql temp_str,N'@new_str varchar(8000) output',@new_string outputselect @new_string as resultreturnGO
@report_id int output
AS
declare @new_string varchar(8000) --变量要加@
declare @Select_str varchar(8000)
declare @from_str varchar(8000)select @select_str=[select],@from_str=[from] --这里原来少个逗号
from server_name.db_name.表A where report_id=@report_iddeclare @temp_str nvarchar(4000)
select replace (@select_str,'','''')
select @temp_str=N'select @new_str='+@select_str+@from_strexec sp_executesql temp_str,N'@new_str varchar(8000) output',@new_string outputselect @new_string as resultreturnGO
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