A powerful full-text search in PostgreSQL in less than 20 lines

seems like ts_rank(to_tsvector(courses.title), query) can give 1e-20 which will not be cast to null. This was causing poor ranking as 1e-20 results are brought to the top

Thank you for the simple and easy to understand post. Is the query still performant with the use of the similarity function?

One thing to note is you'll likely need/want to concatenate the columns you want to search across like this:

to_tsvector(courses.title || ' ' || courses.description)