title: R- sqldf -need explicit units for numeric conversion
body: <p>I need to join 2 tables using a Date field </p>
  
  <pre><code>&gt; class(pagos$pseudo_1mes)
  [1] "Date"
  &gt;  class(pseudo_meses$pseudo_1mes)
  [1] "Date"
  </code></pre>
  
  <p>My code is:</p>
  
  <pre><code>library(sqldf)
  
  pagos&lt;-sqldf("select a.*, b.mes_atras from pagos a 
          left join pseudo_meses b
        on a.pseudo_1mes=b.pseudo_1mes")
  </code></pre>
  
  <p>And I get the following error and no result:</p>
  
  <blockquote>
    <p>Error in asfn(rs[[i]]) : need explicit units for numeric conversion</p>
  </blockquote>
  
  <p>How can I solve it? Thanks</p>