scan and search only a part of the barcode

[BUWANEKA]

hi, there is a 33 digits barcode in printed material. data base has  first 18 digits only. I need to scan barcode and search from database with ignoring last 15 digits.  

eg-

Bar code = 010503238401995317240621104456480  last 15 digits are variables, I only have first 18 digits in my database(eg- 010503238401995317), with scanning full 33 digits barcode need to find data from database, without considering last 15 digits

need help thanks