title: Unknown column in field list error Rmysql
body: <p>I wrote a data.frame using</p>
  
  <pre><code>dbWriteTable(con, name='db_all', df, overwrite=T, row.names=F) 
  </code></pre>
  
  <p>sucessfully to MySQL using RMySQL. 
  Now I have a second data frame which has a similar structure and try to use </p>
  
  <pre><code>dbWriteTable(con,name='db_all',df1,append=T,row.names=F,overwrite=F)
  </code></pre>
  
  <p>which gives me</p>
  
  <blockquote>
    <p>Error in .local(conn, statement, ...) : 
      could not run statement: Unknown column 'zzz' in 'field list'></p>
  </blockquote>
  
  <p>In my SQL table I don't have that column name yet and would expect my append=T  will add this column in my SQL table, which apparently it does not.</p>