title: SQL query to remove left and right characters in a field
body: <p>I have a sql field that i need to edit out characters on the left and right.<br>
  The table name is: cdr<br>
  The field name is: dstchannel<br>
  The dstchannel field shows the following data: Local/872@from-internal-6acb,1<br>
  I just the need the 872 as output<br>
  The field always has the same amount of data, so the 872 will be constaint on its position.<br>
  How would I go about writing a sql query for mysql?  </p>
  
  <p>If I have another query that I want to include this into, how would I do that?  </p>
  
  <p>Thank you</p>