title: How to GROUP BY and CONCATENATE fields in redshift
body: <p>How to GROUP BY and CONCATENATE fields in Redshift e.g.
  If I have table</p>
  <pre><code>ID   COMPANY_ID   EMPLOYEE
  1    1            Anna
  2    1            Bill
  3    2            Carol
  4    2            Dave
  </code></pre>
  <p>How can I get result like this</p>
  <pre><code>COMPANY_ID   EMPLOYEE
  1            Anna, Bill
  2            Carol, Dave
  </code></pre>
  <p><a href="https://stackoverflow.com/questions/43870/how-to-concatenate-strings-of-a-string-field-in-a-postgresql-group-by-query">There are some solutions for PostgreSQL</a>, but none of functions mentioned in those answers are available in Redshift rightnow.</p>