Revision 1d187731-2731-4cb2-923f-a3f0f4ccc272 - Stack Overflow

 CREATE FUNCTION samplefunc() 
 RETURNS TABLE(ntested int, rawscore int, growth int) AS
 $func$
 SELECT count(distinct student_id) -- AS NTested
 ,avg(raw_score)::int -- AS RawScore
 ,avg(growth) -- AS Growth
 FROM reports_results
 WHERE test_type_id = 1
 AND test_id = '201403MAME04'
 $func$ LANGUAGE sql;

- The clause to return a table is [**`RETURNS TABLE`**][1]

Also:

- column aliases are only visible inside the function. If you are not going to reference them *inside* the function, they are just documentation.
- What's with the capitalization? Unquoted identifiers are cast to lower case in Postgres automatically.


 [1]: http://www.postgresql.org/docs/current/interactive/sql-createfunction.html