Can't update or delete

[powers]

I'm having a problem with my updating and deleting scripts
My query

$queryupdate = "select * from customer where customer_id = '$customer_id'";

doesn't seem to be able to retrieve the details of the record to be updated unless the first record in the table has a customer_id value of 0. When the first record has a $customer_id=0 it is the only record it retrieves, otherwise I get a blank page with only the submit and reset buttons or 'cannot find record' in the case of the delete script.
Any ideas??

[powers]

Figured it out after reading the post by damian742.

I edited the query below

$queryupdate = "select * from customer where customer_id = '$customer_id'";

to read

$queryupdate = "select * from customer where customer_id = '$id'";

My update forms now display data that i can amend!

Thanx Damian!