insert 一个参数给存储过程问题

Question

      现在有表student，字段studentId，studentName，today
      表studentOne，字段studentId,studentName
      现在有存储过程：
      create procedure prstudent
      @today dateTime
      as
      exec ('insert into student(studentId,studentName,today)
            select *,'+@today+'
            from studentOne' )      现在希望把：@today参数的日期值 添加到student中
      上面存储过程错误，请教

Answer 1

exec ('insert into student(studentId,studentName,today)
            select *,'''+@today+'''
            from studentOne' )

Answer 2

exec ('insert into student(studentId,studentName,today) 
            select *,'''+@today+''' 
            from studentOne' ) 

Answer 3

create procedure prstudent
      @today dateTime
      as
      declare @sql varchar(8000)
      select @sql = 'insert into student(studentId,studentName,today)
            select *,'''+convert(varchar(20),@today,120)+'''
            from studentOne' 
      exec (@sql)