请教这sql哪里有错?多谢_Sql Server

请问这sql哪里有错?在线等,谢谢
set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
go
alter FUNCTION [dbo].[GetChildId](@ClassId int)
RETURNS table
AS
[email protected]
declare @LastNode int 提示这里有错
--定义游标,
Declare table_sursor Cursor for Select LastNode from Class where ParentId [email protected]
--打开游标
open table_sursor
--提取第一行记录,[email protected]
Fetch next from table_sursor into @LastNode
--检查@@Fetch_Status以确定是否还可以继续取数
while @@Fetch_Status = 0
begin
if(@LastNode = 1)
begin
SELECT ClassName,ClassId From Class where ParentId [email protected]
end
Fetch next from table_sursor into @LastNode

end

消息 156，级别 15，状态 1，过程 GetChildId，第 5 行
关键字 'declare' 附近有语法错误。

------解决方案--------------------

SQL code

Declare     table_sursor   Cursor   for   Select   LastNode   from   Class   where   ParentId   [email protected] -->Declare     table_sursor   Cursor   LOCAL STATICREAD_ONLYfor   Select   LastNode   from   Class   where   ParentId   [email protected]
------解决方案--------------------
set   ANSI_NULLS   ON  
set   QUOTED_IDENTIFIER   ON  
go  
alter   FUNCTION   [dbo].[GetChildId](@ClassId   int)  
RETURNS   table  
AS  
begin
[email protected]  
declare   @LastNode   int     提示这里有错  
--定义游标,  
Declare     table_sursor   Cursor   for   Select   LastNode   from   Class   where   ParentId   [email protected]  
--打开游标  
open   table_sursor  
--提取第一行记录,[email protected]  
Fetch   next   from   table_sursor   into   @LastNode  
--检查@@Fetch_Status以确定是否还可以继续取数  
while   @@Fetch_Status   =   0  
begin  
         if(@LastNode   =   1)  
         begin  
              SELECT   ClassName,ClassId   From   Class   where   ParentId   [email protected]                
         end  
       Fetch   next   from   table_sursor   into   @LastNode  

end  
close table_sursor
deallocate table_sursor
end
------解决方案--------------------
呵呵，少了
begin
end

------解决方案--------------------
函数不能 select 返回数据,应该定义table变量,然后插入数据,然后return 那个表