存储过程 IN 的问题
PROCEDURE   Test
(
        @PeopleList         ntext
)
AS

SELECT   UserID
From   UserTable
WHERE
UserID   IN   ( '   +   @PeopleList   +   ')

上面是错误的,   怎么解决


如:我的参数是(C#):  

command.Parameters.Add( "@PeopleList ",   SqlDbType.NText).Value   =   "3,5,2 ";

------解决方案--------------------
PROCEDURE Test
(
@PeopleList ntext
)
AS
EXEC( '
SELECT UserID
From UserTable
WHERE
UserID IN ( ' + @PeopleList + ')
')
------解决方案--------------------
--用动态SQL语句。


create PROCEDURE Test
(
@PeopleList ntext
)
AS

EXEC( 'SELECT UserID From UserTable WHERE UserID IN ( ' + @PeopleList + ') ')

------解决方案--------------------

动态sql语句基本语法
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,
@sql nvarchar(4000)
set @sql= 'select count(*) from tableName '
exec(@sql)


--如何将exec执行结果放入变量中？

declare @num int, @sql nvarchar(4000)
set @sql= 'select @a=count(*) from tableName '
exec sp_executesql @sql,N '@a int output ',@num output
select @num


------解决方案--------------------
如果不想使用动态SQL,可以使用in的替代方法:charindex,例如:
PROCEDURE Test (@PeopleList ntext)
AS
SELECT UserID From UserTable
WHERE charindex(N ', ' + UserID + N ', ',N ', ' + @PeopleList + N ', ') > 0
GO
------解决方案--------------------
PROCEDURE Test (@PeopleList ntext)
AS
SELECT UserID From UserTable
WHERE charindex(N ', ' + UserID + N ', ',N ', ' + @PeopleList + N ', ') > 0
GO
--还可以
PROCEDURE Test (@PeopleList ntext)
AS
SELECT UserID From UserTable
WHERE patindex(N '%, ' + UserID + N ',% ',N ', ' + @PeopleList + N ', ') > 0
GO

PROCEDURE Test (@PeopleList ntext)
AS
SELECT UserID From UserTable
WHERE N ', ' + UserID + N ', ' like N ', ' + @PeopleList + N ', '
GO