title: Error 00937 "not a single-group group function"
body: <p>i face ORA-00937: &quot;not a single-group group function&quot; error problem with this sql query:
  Any ideas please ! Thanks.</p>
  <pre><code>SELECT avg(count(*)) as value, 'Taux remplissage' as serie, to_char(c.datcre, 'YYYY-MM-DD') as arg
  from charge c left join emplac e ON c.adr = e.adr 
  where e.ADR is not null and e.empsta != 'I' and e.empsta != 'V'
  and (trunc(c.datcre) &gt;= to_date('2020-11-01','YYYY-MM-DD'))
  and (trunc(c.datcre) &lt;= to_date('2021-11-30','YYYY-MM-DD'))
  GROUP BY to_char(c.datcre, 'YYYY-MM-DD')
  ORDER BY arg, serie
  </code></pre>