title: SQL - about HAVING clause
body: <p>Below is a sample question from Oracle</p>
  
  <p>Q) Which of the following statements is true about HAVING? (Choose two.)</p>
  
  <p>A. It can be used only in the SELECT statement.</p>
  
  <p>B. It must occur after the GROUP BY clause.</p>
  
  <p>C. It must occur after the WHERE clause.</p>
  
  <p>D. It cannot reference an expression unless that expression is first reference in the GROUP BY clause.</p>
  
  <p>To me, the answers should be A &amp; B. The actual answers are A &amp; C. "HAVING cannot be used without GROUP BY, but it is not required to follow GROUP BY". </p>
  
  <p>Is that statement correct? Please advice.</p>