SQL从数据类型 nvarchar 转换为 bigint 时出错解决方案

--添加表值函数
 1 ALTER function [dbo].[func_splitstring]
(@str nvarchar(max),@split varchar(10))
returns @t Table (id varchar(100))
as
begin
    declare @i int
    declare @s int
    set @i=1
    set @s=1
    while(@i>0)
    begin    
        set @i=charindex(@split,@str,@s)
        if(@i>0)
        begin
            insert @t(id) values(substring(@str,@s,@i-@s))
        end   
        else begin
            insert @t(id) values(substring(@str,@s,len(@str)-@s+1))
        end
        set @s = @i + 1   
    end
    return
end

ALTER PROCEDURE [dbo].[GetStudentListByStudentId]
@StudentId nvarchar(500)
as
BEGIN
--调用表值函数转换类型
select * from Student where StudentId in(SELECT cast(id as int) StudentId FROM dbo.func_splitstring(@StudentId,','))
end