Elixir: How to search database data with double spaces - postgresql

Question

In my front end, the data display has only single spaces. However, when I filter my data in search bar, it yields no result. It turns out the data actually has double spaces. But when its being repo.all, the double spaces becomes single spaces. I need to search that data.
I have a regexp which i found which i tried in pgadmin which works. I need to replicate it in my elixir datatable, for specifically, integrating it in ilike function.
The regexp is
SELECT trim(regexp_replace(name, '\s+', ' ', 'g')) as col_name
FROM table where col_name = 'TEST DATA'

Answer 1

I think a better approach might be to use % in place of spaces when searching, I find that this gives me generally better results. Here are the docs for ILIKE in Postgres, but I'll explain with an example. The % character used in ILIKE matches any string of characters (including the empty string).
SELECT * FROM t1 WHERE col_name ILIKE '%test%data%';
The query above will match the example that you've given. Granted, it will also match strings like "testdata", "test data", "something test something data", but I think that in general this approach will return results that a user would expect when entering a search like "test data".
A helper function to do this transformation from user input to a string suitable for Ecto's ilike would look like this:
defmodule SearchHelpers do
def to_ilike_search_string(search_string) do
joined_string =
search_string
|> String.split()
|> Enum.join("%")
"%#{joined_string}%"
end
end
# SearchHelpers.to_ilike_search_string("test data")
# => "%test%data%"
And you could use it in a query like this:
ilike_search_string = SearchHelpers.to_ilike_search_string("test data")
query = from p in Post,
where: ilike(p.content, ^ilike_search_string)
results = Repo.all(query)
Good luck, hope this helps.