title: Unknown column in where clause?
body: <p>My code:</p>
  
  <pre><code>drop table if exists HSstudents;
  
  create table HSstudents 
  (
       HSsID int, 
       vNAAM text, 
       aNAAM text, 
       LT int, 
       GM float
  );
  
  insert into HSstudents values (1, 'Thomas', 'Jansen', 18, 7.0);
  insert into HSstudents values (2, 'Jesse', 'Bakker', 19, 6.5);
  insert into HSstudents values (3, 'Tom', 'Smit', 20, 7.1);
  insert into HSstudents values (4, 'Jelle', 'Visser', 17, 9.6);
  insert into HSstudents values (5, 'Sem', 'Dekker', 17, 8.1);
  insert into HSstudents values (6, 'Anna', 'Peters', 18, 6.8);
  insert into HSstudents values (7, 'Michelle', 'Hendriks', 19, 8.2);
  insert into HSstudents values (8, 'Senna', 'Mulder', 20, 5.9);
  insert into HSstudents values (9, 'Sven', 'Linden', 21, 6.0);
  insert into HSstudents values (10, 'Ilse', 'Jacobs', 21, 7.5);
  insert into HSstudents values (11, 'Harm', 'Schouten', 19, 7.0);
  insert into HSstudents values (12, 'Emma', 'Dijkstra', 18, 8.1);
  
  drop table if exists students;
  
  create table students 
  (
       sID int, 
       vNAAM text, 
       aNAAM text, 
       LT int
  );
  
  insert into students values (1, 'Thomas', 'Jansen', 18);
  insert into students values (2, 'Jesse', 'Bakker', 19);
  insert into students values (3, 'Tom', 'Smit', 20);
  insert into students values (4, 'Jelle', 'Visser', 17);
  insert into students values (5, 'Sem', 'Dekker', 17);
  insert into students values (6, 'Anna', 'Peters', 18);
  insert into students values (7, 'Michelle', 'Hendriks', 19);
  insert into students values (8, 'Senna', 'Mulder', 20);
  insert into students values (9, 'Sven', 'Linden', 21);
  insert into students values (10, 'Ilse', 'Jacobs', 21);
  insert into students values (11, 'Harm', 'Schouten', 19);
  insert into students values (12, 'Emma', 'Dijkstra', 18);
  
  drop table if exists applications;
  
  create table applications 
  (
      sID int, 
      aPROV text, 
      sPROV text, 
      taal text
  );
  
  insert into applications values (1, 'Overijssel', 'Drenthe', 'HTML');
  insert into applications values (2, 'Gelderland', 'Overijssel', 'CSS');
  insert into applications values (3, 'Groningen', 'Flevoland', 'CSS');
  insert into applications values (4, 'Overijssel', 'Zuid-Holland', 'SQL');
  insert into applications values (5, 'Noord-Holland', 'Drenthe', 'C#');
  insert into applications values (6, 'Flevoland', 'Groningen', 'C#');
  insert into applications values (7, 'Limburg', 'Groningen', 'JAVA');
  insert into applications values (8, 'Limburg', 'Limburg', 'JAVASCRIPT');
  insert into applications values (9, 'Drenthe', 'Noord-Brabant', 'CSS');
  insert into applications values (10, 'Drenthe', 'Zeeland', 'Python');
  insert into applications values (11, 'Zuid-Holland', 'Friesland', 'C++');
  insert into applications values (12, 'Zeeland', 'Friesland', 'JAVA');
  
  select 
      S.sID, S.vNAAM, S.aNAAM, S.LT, aPROV, sPROV, taal
  from 
      HSstudents HS, students S, applications A
  where 
      HSstudents.HSsID = students.sID
  </code></pre>
  
  <p>This results in an error</p>
  
  <blockquote>
    <p>Code: 1054. Unknown column 'HSstudents.HSsID' in 'where clause'</p>
  </blockquote>
  
  <p>How? Shouldn't it just work?</p>