关于SQL语句的一个有关问题_ASP.NET

关于SQL语句的一个问题
怎样在存储过程里写一个SQL插入语句，判断同一个用户在一天内执行两次插入后不再执行第三次？
字段名有username和datetime

------解决方案--------------------------------------------------------
用函数返回该用户今天发布信息的条数小于2 就执行这条插入语句

if(function(select count(*) from User where username= name and datetime = date())< 2)
insert into User ....

乱写的是这个意思
------解决方案--------------------------------------------------------

SQL code

create proc ProcNameas    declare @count int    select count(*) from TableName where username = '' and datediff(day,biday,getdate())=0     if(@count <= 2)    begin        insert into .....//插入语句    endgo
------解决方案--------------------------------------------------------
探讨
SQL code
create proc ProcName
as
    declare @count int
    select count(*) from TableName where username = '' and datediff(day,biday,getdate())=0 

    if(@count <= 2)
    begin
        insert into .....//插入语句
    end
go




试试吧！

------解决方案--------------------------------------------------------
create proc ProcName
@UserID varchar(20)=''
as
   declare @count int
   select count(*) from TableName where username =@UserID and datediff(day,biday,getdate())=0  

   if(@count <= 2)
   begin
       insert into .....//插入语句
   end
go