Hi all I got website that got database in mysql is there a easy way to email them all at once ??

Yep,

Loop through the records and construct a message for each user in whatever server side code you are using.

Just loop through but keep a batch of 100 or 200 ( depending on time it takes ) email at a time.

I've found that when you have lots of email addresses, it's easier to run the php script that does your email from the command line instead of a browser. This is because there is a timeout limit in Apache that will stop your script after X amount of seconds.