title: How to set group by for multiple fields in sphinx config source sql
body: <p>I need to set group by for multiple fields in my sphinx config source sql. </p>
  
  <pre><code>select f1,f2,f3,f5 from table group by f2,f3,f5;
  </code></pre>
  
  <p>Like this I need sql</p>
  
  <p>for that I created source like this</p>
  
  <pre><code>source myindex
  {
      type            = mysql
  
      sql_host        = localhost
      sql_user        = root
      sql_pass        = root
      sql_db          = mydb
      sql_port        = 3306  # optional, default is 3306
      sql_query = \
      select f1,f2,f3,f4 from table;
  
      sql_group_column = f2;
      sql_group_column = f3;
      sql_group_column = f4;
  
  }
  </code></pre>
  
  <p>My I know my config file is correct or not?</p>
  
  <pre><code>WARNING: key 'sql_group_column' is deprecated in /etc/sphinx/sphinx.conf line 27; use 'sql_attr_uint' instead
  </code></pre>
  
  <p>My sphinx version is 204. Now I am getting this error while rotating my index.</p>