title: String functions in a SQL where clause
body: <p>Lets say I have a field. Lets call it Barcode1. Right now all Barcodes1 are 22 characters with each character is an integer. 
  Suppose there is a second field Barcode2. Both of these are <code>varchar(22)</code></p>
  
  <p>My condition in plain english terms is:
  Barcode1 is identical to barcode2 except in digits 7,8 where for barcode2, digits 7 and 8 are the same thing in barcode1 <strong>plus 20</strong> </p>
  
  <p>so </p>
  
  <pre><code>001214**54**54545654521523
  549462**74**48634842135782
  </code></pre>
  
  <p>I also would like the negation of the where clause where rows that do NOT match the condition are returned. </p>
  
  <p>Thank you.</p>