title: Updating one table with data from other tables. (With addition)
body: <p>I have two simple tables: </p>
  
  <pre><code>Table: POP_UP (ACC_NR, AMOUNT);
  Table: ACCOUNT (ACC_NR, SUM, CUST_ID); 
  </code></pre>
  
  <p>And I am trying to figure out how to update SUM in Table ACCOUNT, when I am entering information in to the table POP_UP. Should I go with trigers or is there are another way to do so?</p>