Create a million record with random strings, 10% of them will have hanging whitespace, 10% will have trailing whitespace

insert-random-data-with-trailing-withespace.sql

insert into
  trailing_spaces (value)
select
  case
    when mod(indx, 9) = 0 then 'A' || (random() * 100)::text || ' '
    when mod(indx, 10) = 0 then ' B' || (random() * 100)::text
    else 'C' || (random() * 100)::text
  end
from
  generate_series(1, 1000000) as d (indx)
;