title: MySQL statement for group_concat in Update from two other tables
body: <p>I have 3 tables below I'm trying to write a <code>group_concat</code> statement for the "item" column in the table cart_session </p>
  
  <p>TABLE <code>products</code></p>
  
  <pre><code>id      name
  ------------------------
  123  |  car
  456  |  boat
  789  |  house
  
  --------------------------------
  </code></pre>
  
  <p>TABLE <code>cart_items</code></p>
  
  <pre><code>pid session
  ----------------------
  123  |  ABCD    
  456  |  ABCD
  789  |  EFGH
  
  ----------------------------------
  </code></pre>
  
  <p>TABLE <code>cart_session</code></p>
  
  <pre><code>id   item
  ----------------------------
  ABCD  |  car,boat
  EFGH  |  house
  </code></pre>