title: PHP/MYSQL: How can I calculate value of field + other field + other field
body: <p>I've got a mysql table, which contains a field called 'id', 'name' and 'number'.</p>
  
  <p>Every row's field 'number', has got a number.</p>
  
  <pre><code>id   name   number
  
  1    test 30
  
  2    test2  40
  
  3    lala   23
  
  
  total = 93
  </code></pre>
  
  <p>How can I calculate (plus) all the rows' number?</p>
  
  <pre><code>$row['number']+$row['number']+$row['number'] = .. an other number.
  </code></pre>