Can't connect MySQL through PHP
 

When I run the page, it appears:

Fatal Error : Call to undefined function : mysql_connect() in connectDB.php on line 4

I'm using RedHat 7.2 and have MySQL installed.
Is there any things need to be configured or installed?

Help!!

Try running a phpinfo() page, and look to see if php is configured to work with MySQL. I have Red Hat 7.0, and php and Apache came configured to work with PostgreSQL rather than MySQL.

You may need to ./configure the php module to recognize MySQL. Check out the man pages and HOWTOs for configuration help with php.