select *
from description
where
  term ilike %% 'query'
order by
  term ilike 'query'  -- prefer exact match
  term ilike 'query'  -- prefer starts with
--  term %% 'query'     -- fill with fuzzy trigram match
limit 10

-- select * FROM (

  select *       -- 100 ms when run alone
  FROM  description d
  where term ilike 'hyp'
UNION
  select * from (  -- 100 ms when run alone, returns 1000 rows if no limit
      select *
      FROM  snomed_ct.description d
      where  d.term ilike 'hyp%'
  ) as x
UNION
  select *   -- 200ms seconds when run alone (with limit 10)
  FROM  description d
  where   d.term % 'hyp'
-- ) as d
limit 10

select *
      FROM  description d
      where   d.term % 'hyp'

selects = [select1_iterator, select2_iterator, select3_iterator, ]
iter = chain(selects) # pick from 1st iterator, then second, then 3rd
iter = duplicated(selects) # skip duplicates
iter = limit(selects, 10)  # pick 1st 10