title: Comma separated string of selected values in MySQL
body: <p>I want to convert selected values into a comma separated string in MySQL.</p>
  <p>My initial code is as follows:</p>
  <pre><code>SELECT id
  FROM table_level
  WHERE parent_id = 4;
  </code></pre>
  <p>Which produces:</p>
  <pre><code>'5'
  '6'
  '9'
  '10'
  '12'
  '14'
  '15'
  '17'
  '18'
  '779'
  </code></pre>
  <p>My desired output would look like this:</p>
  <pre><code>&quot;5,6,9,10,12,14,15,17,18,779&quot;
  </code></pre>