--方法2:字段名，表名，数据库名之类作为变量时,用动态SQL
declare @FName varchar(20)
set @FName='ID'
exec('select '+@FName+' from sysobjects where '+@FName+'=5' )


declare @s varchar(1000)
set @s=N'select '+@FName+' from sysobjects where '+@FName+'=5'
exec sp_executesql @s--会报错


declare @s nvarchar(1000)--改为nvarchar
set @s=N'select '+@FName+' from sysobjects where '+@FName+'=5'
exec sp_executesql @s--成功

--方法3:输入参数

declare @i int,@s nvarchar(1000)
set @i=5
exec('select ID,Name from sysobjects where ID='+@i)

set @s='select ID,Name from sysobjects where ID=@i'
exec sp_executesql @s,N'@i int',@i--此处输入参数要加上N

--方法4:输出参数

declare @i int,@s nvarchar(1000)
set @s='select @i=count(1) from sysobjects'

--用exec
exec('declare @i int '+@s+' select @i')--把整个语句用字符串加起来执行

--用sp_executesql
exec sp_executesql @s,N'@i int output',@i output--此处输出参数要加上N
select @i

--方法5:输入输出

--用sp_executesql
declare @i int,@con int,@s nvarchar(1000)
set @i=5
select @s='select @con=count(1) from sysobjects where ID>@i'
exec sp_executesql @s,N'@con int output,@i int',@con output ,@i
select @con

--用exec
declare @i int,@s nvarchar(1000)
set @i=5
select @s='declare @con int select @con=count(1) from sysobjects where ID>'+rtrim(@i)+' select @con'
exec(@s)

实例：

   问题：

declare @test varchar(1000)
declare @total Integer
SET @test= '21,23,24,25,26,27'

EXEC ('
   declare @count Integer
   select @count=count(*) from NeiEntityContainmentTable
   WHERE myentitytype in (' + @test + ')')

我想将@count的结果返回到@total中，如何？？？



回答：

---------------------------------------------------------------

declare @test Nvarchar(1000)
declare @total Int
declare @sql Nvarchar(1000)

SET @test= N'21,23,24,25,26,27'

set @sql=N'
   select @count=count(*) from NeiEntityContainmentTable
   WHERE myentitytype in (' + @test + N')'

exec   sp_executesql   @sql,   N'@count   int output',   @total   output