Merge two rows from a table in a single row
@a_horse_with-no_name's query improved:

SELECT "contactId", 
        email, 
        company
FROM 
    ( SELECT "contactId", "value" AS email
      FROM "contactFields"
      WHERE "fieldType" = 'email'
        AND "order" = 0
    ) AS e
  FULL JOIN 
    ( SELECT "contactId", "value" AS company
      FROM "contactFields"
      WHERE "fieldType" = 'company'
        AND "order" = 0
    ) AS c 
  USING ("contactId") ;