select * FROM (
  SELECT language_id,id AS object_id,NULL AS method_id,NULL AS property_id,NULL AS constant_id, 60 AS weight FROM objects o WHERE name ILIKE '%svg%'
  UNION
  SELECT language_id,id AS object_id,NULL,NULL,NULL,30 AS weight FROM objects o WHERE overview ILIKE '%svg%'
  UNION
  SELECT language_id,id AS object_id,NULL,NULL,NULL,10 AS weight FROM objects o WHERE description ILIKE '%svg%'
) AS stuff LIMIT 5;
#  language_id | object_id | method_id | property_id | constant_id | weight
# -------------+-----------+-----------+-------------+-------------+--------
#            1 |         1 |           |             |             |     10
#            1 |         1 |           |             |             |     30
#            1 |         1 |           |             |             |     60
#            1 |         2 |           |             |             |     60
#            1 |         3 |           |             |             |     60
# (5 rows)


select * from (
  SELECT language_id,NULL,m.id,NULL,NULL,60 AS weight FROM methods m
    INNER JOIN objects o ON m.object_id=o.id WHERE m.name ILIKE '%svg%'
  UNION
  SELECT language_id,NULL,m.id,NULL,NULL,20 AS weight FROM methods m
    INNER JOIN objects o ON m.object_id=o.id WHERE m.overview ILIKE '%svg%'
  UNION
  SELECT language_id,NULL,m.id,NULL,NULL,5 AS weight FROM methods m
    INNER JOIN objects o ON m.object_id=o.id WHERE m.description ILIKE '%svg%'
  UNION
  SELECT language_id,NULL,method_id,NULL,NULL,10 AS weight FROM arguments a
    INNER JOIN methods m ON a.method_id=m.id
    INNER JOIN objects o ON m.object_id=o.id WHERE a.name ILIKE '%svg%'
  UNION
  SELECT language_id,NULL,method_id,NULL,NULL,5 AS weight FROM arguments a
    INNER JOIN methods m ON a.method_id=m.id
    INNER JOIN objects o ON m.object_id=o.id WHERE a.overview ILIKE '%svg%'
) AS morestuff LIMIT 5;
#  language_id | ?column? | id  | ?column? | ?column? | weight
# -------------+----------+-----+----------+----------+--------
#            1 |          | 442 |          |          |      5
#            1 |          | 460 |          |          |     60
#            1 |          | 461 |          |          |     60
#            1 |          | 462 |          |          |     60
#            1 |          | 463 |          |          |      5
# (5 rows)


select * FROM (
  SELECT language_id,id AS object_id,NULL AS method_id,NULL AS property_id,NULL AS constant_id, 60 AS weight FROM objects o WHERE name ILIKE '%svg%'
  UNION
  SELECT language_id,id AS object_id,NULL,NULL,NULL,30 AS weight FROM objects o WHERE overview ILIKE '%svg%'
  UNION
  SELECT language_id,id AS object_id,NULL,NULL,NULL,10 AS weight FROM objects o WHERE description ILIKE '%svg%'
) AS stuff UNION select * FROM (
  SELECT language_id,NULL,m.id,NULL,NULL,60 AS weight FROM methods m
    INNER JOIN objects o ON m.object_id=o.id WHERE m.name ILIKE '%svg%'
  UNION
  SELECT language_id,NULL,m.id,NULL,NULL,20 AS weight FROM methods m
    INNER JOIN objects o ON m.object_id=o.id WHERE m.overview ILIKE '%svg%'
  UNION
  SELECT language_id,NULL,m.id,NULL,NULL,5 AS weight FROM methods m
    INNER JOIN objects o ON m.object_id=o.id WHERE m.description ILIKE '%svg%'
  UNION
  SELECT language_id,NULL,method_id,NULL,NULL,10 AS weight FROM arguments a
    INNER JOIN methods m ON a.method_id=m.id
    INNER JOIN objects o ON m.object_id=o.id WHERE a.name ILIKE '%svg%'
  UNION
  SELECT language_id,NULL,method_id,NULL,NULL,5 AS weight FROM arguments a
    INNER JOIN methods m ON a.method_id=m.id
    INNER JOIN objects o ON m.object_id=o.id WHERE a.overview ILIKE '%svg%'
) AS morestuff LIMIT 5;
# ERROR:  UNION types integer and text cannot be matched