title: Join considering length of characters
body: <p>I am trying to do a left join based on the number of characters. In the destination_postal_code column I hace a more deailed postcode value. In the dest_postal_code_prefix I have only the first few digits of a postcode. When I join I would like to output to consider this:</p>
  
  <pre><code>destination_postal_code     dest_postal_code_prefix
  2345                        23
  3356                        33
  5672                        567
  </code></pre>
  
  <p>For now I have :</p>
  
  <pre><code>SELECT DISTINCT 
  p.destination_postal_code
  FROM posimorders.atrops_ddl.o_slam_packages p
  LEFT JOIN posimorders.sc_execution_eu.o_transit_time_pad t
  ON p.destination_postal_code = t.dest_postal_code_prefix
  </code></pre>
  
  <p>The expected output would be </p>
  
  <pre><code>destination_postal_code 
  2345                        
  3356                        
  5672                        
  </code></pre>
  
  <p>In the output it can be seen that, when my prefix is 23, I want all psotcodes begining with 23.. to be in mu output and so on</p>