Pre printing studio SQL injection and repair

Title: pre printing studio SQL Injection
Author: infosecpirate@gmail.com of r45c4l www.2cto.com
Program: http://www.preprojects.com/preprojects/printing.asp
Product Introduction:
A complete printing press website script contains all features required for online printing business. developed in PHP, MYSQL and Flash AS3, with all browsers compatibility and easy to navigate. package contains builtin designers to customize designs online, shopping cart and complete users and orders modules. product is user friedly and can fully operate via secure admin panel. script is fully customizable and ready to upload to start your printing press now.
Product Price: 999 $
Test method --- ICW ---
[Explain 0! T]
SQL Injection
P0c-http://www.bkjia.com/preprojects/prestudio/page. php? Id = [SQli]

Some intresting tables and columns:
Table: admin Columns: password, username, id
Table: users columns: email, id
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Fix: Filter