title: Clickhouse - join on string columns
body: <p>I got <em>String</em> column <code>uin</code> in several tables, how do I can effectively join on <code>uin</code> these tables?</p>
  
  <p>In Vertica database we use <code>hash(uin)</code> to transform string column into hash with <em>Int</em> data type - it significantly boosts efficiency in joins - could you recommend something like this? I tried <code>CRC32(s)</code> but it seems to work wrong.</p>