title: WHERE clause in sub-query
body: <p>Following SQL query:</p>
  
  <pre><code>select *  from er_101
   where cd_relnaam IN ( 
       select cd_relnaam 
       from er_101 
       group by cd_relnaam 
       having count(*) &gt; 1)
   AND ld_relopdrachtgever = '1'
  </code></pre>
  
  <p>Though I need to have that sub query also limits on <code>ld_relopdrachtgever = '1'</code><br>
  How is that possible with an HAVING statement?</p>