Joining Custom Object table with incidet Table

Summary

I want to join my cusotm object table with the incident table using the ref_no field

Content

I have a custom object that contains the ref_no field that I have imported into RightNow I want to join it with the incident ref_no field to be able to pull data.   Unlike other oracle data bases it will not allow me to create a join on the like fields.  How can I join these two table to be able to pull the data and report on what I need to report on.  I need to do a simple report that if the custom object ref_no is equal to the incident ref_no then list out the contact info from the incident