title: Oracle SQL ORA-00937: not a single-group group function
body: <p>I am trying to search for accounts which are of type 'Savings' but the following extract of code is giving me error "ORA-00937: not a single-group group function" - does anyone know why I am getting this error?</p>
  
  <pre><code>SELECT b.bID as "Branch Number", COUNT(a.accNum) as "# of Saving Accounts"
  from branchtable b, accounttable a
  where a.bId = b.bID
  and a.acctype = 'Savings';
  </code></pre>