title: SQL SELECT FROM ... AS with data type specifier?
body: <p>I have a problem with an SQL query on Postgresql. This select clause is an example from a lecture on databases:</p>
  
  <pre><code>1 select t.CourseNr, t.StudentsPerCourse, g.StudentCount, 
  2        t.StudentsPerCourse/g.StudentCount as Marketshare
  3 from (select CourseNr, count(*) as StudentsPerCourse
  4       from taking
  5       group by CourseNr) t,
  6      (select count(*) as StudentCount
  7       from Students) g;
  </code></pre>
  
  <p>The problem is the Marketshare column in line 2. Both StudentsPerCourse and StudentCount are of type integer.</p>
  
  <p>When using this on my Postgresql database, the Marketshare column is evaluated as an int type, while i would need a float/numeric here. I didn't find any way to specify the data type by searching the Postgresql Documentation on SELECT clauses nor by googling. Is there a (preferably standard SQL) way to specify the column type or am I missing something here?</p>