title: Random pick from a Table using RAND() does not work properly
body: <p>I created a table consists of two columns, <code>id</code> and <code>name</code>.</p>
  
  <pre><code>create table City(id integer, name varchar(100));
  insert into City(id, name) values (1, "Jakarta"), (2, "Bandung"), (3, "Tangerang"), (4, "Depok"), 
  (5, "Surabaya"), (6, "Lampung"), (7, "Balikpapan"), (8, "Bogor");
  </code></pre>
  
  <p>I would like to pick a row randomly via the <code>id</code>. The code <code>select floor(rand()*8) + 1</code> works fine. It does give random integers from 1 to 8. </p>
  
  <p>The line</p>
  
  <pre><code>select * from City where id = floor(rand()*8) + 1
  </code></pre>
  
  <p>should always return one row only from <code>City</code>. But when I tried, it sometimes return more than one row, or even none. Why is this? thanks.</p>