title: INTERVAL duration literals in TDEngine
body: <p>I am <a href="https://docs.tdengine.com/taos-sql/interval" rel="nofollow noreferrer">not able to find</a> duration literals used by INTERVAL keyword in TDEngine. E.g. <code>select count(*) from mytable interval(1m);</code> works for 1-minute intervals, but I don't know what letter should be used for 1-month interval. I would like to know all possible duration intervals available.</p>