title: update mysql field using CONCAT function?
body: <p>i need a simple query which update mysql field with its value and some modification for example if field have value (3,4,5) i can add (,6) and this just in case it have value and if its NULL then update the field with the ","</p>
  
  <p>i searched web and find mysql function called CONCAT and it Returns the string that results from concatenating the arguments.</p>
  
  <p>i tried this one but this didn't work</p>
  
  <pre><code>UPDATE groups SET SubsID = CONCAT(SubsID,",5") WHERE GroupID = 2
  </code></pre>
  
  <p>it return no issue but 0 rows affected and field not updated</p>