hello

I have a login page for users with user name and password.
I want to insert the user name in another table (eg login table) only one time so if the user name is aready in the login table and the user login second time it will not insert again in the login table

please help as soon as possible

I am not sure what you mean but if you are trying to only have a unique set of usernames in that table you would do something like this in SQL:

IF NOT EXISTS(SELECT username FROM table where username = @username)
   Begin
        INSERT INTO table (username) values(@username)
   End

--Stole this from a moderator

I will only tell you how to do it, not do it for you.
Unless, of course, you want to hire me to do work for you.