PHP doubt

Hey guys, I have written a program and being a newbie I dont know if this is good or will give me problems in the future, so will appreciate it if you could just have a look at the function and give me your "esteemed opinion" ;-) This is just a snip from the program...its pretty easy so your guru's should have no problem figuring it out. // connected to the database successfully and running this query: { mysql_query.........etc $r=select max(cno)+1 from customer; insert into customer values($r,'$name'); } print("Your customer number is: $r"); what do you think? And will this return the correct values if 2 people submitted the form at the same time? Cheers, -Ryan.