title: R dplyr join on range of dates
body: <p>I want to join two tables <code>xxx</code> and <code>yyy</code> using a composite unique key and date ranges. In sql I would simply specify in the join but I cannot get <code>dplyr</code> to work. Is this possible? </p>
  
  <pre><code>test&lt;- inner_join(xxx, yyy, by = c("ID" = "ID",
                                 "NRA"="NRA",
                                 "date_low"&gt;"date",
                                 "date_high"&lt;"date"),
                                 copy = FALSE)
  </code></pre>