title: count showing keyword not found where expected
body: <p>I am vey new to sql.<br>I encountered a question while practicing<br><br>
  Find the difference between the total number of CITY entries in the table and the number of distinct CITY entries in the table.
  The STATION table is described as follows:
  <a href="https://i.stack.imgur.com/7Z3p5.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7Z3p5.jpg" alt="table structure" /></a></p>
  <p>I wrote this as answer:</p>
  <pre><code>select (select count(city) from station)-
  (select distinct count(city) from station)
  from station;
  </code></pre>
  <p>and this error is being shown(below).</p>
  <pre><code>select (select count(city) from station) (select distinct count(city) from station)
  *
  ERROR at line 1:
  ORA-00923: FROM keyword not found where expected
  </code></pre>
  <p>why such an error?</p>