title: Subtracting months from date using Redshift
body: <p>I know I can use dateadd to add an interval to a date, what about subtracting, would I just use a negative number? Here is an example:</p>
  
  <pre><code>select "date_table"."id_date" &gt;= date_trunc('month', dateadd(month,-18, current_date)) 
  from "date_table"
  </code></pre>