if user name already exists in data base

[ankit chopra]

if the user details already exists in php my admin data base like user name and pass then submit a form a alert show user value already exists

[Luuk]

Where is the question you would like to ask?

What is a 'data base' ? (a database is an organized collection of data )

What is 'php my admin'? (phpMyAdmin is a free software tool written in PHP)

and finally,
If the username, and password already exist, normally this will result in a logon to your application. So, why show an alert?