Hey
I want to introduce you a small utility that may help in writing dynamic queries

In a few words, this code:

blank_string? = fn string -> String.trim(string) == "" end
query = some_complex_query()

query =
  if not is_binary(params[:some_field1]) or blank_string?.(params[:some_field1]) do
    query
  else
    query |> where(some_field1: ^params[:some_field1])
  end

query =
  if is_nil(params[:some_field2]) do
    query
  else
    query |> where(some_field2: ^params[:some_field2])
  end

query |> Repo.all()

can be reorganzied to this:

blank_string? = fn string -> String.trim(string) == "" end

some_complex_query()
|> Composite.new(params)
|> Composite.param(:somefield1, &where(&1, some_field1: ^&2),
  ignore?: &(not is_binary(&1) or blank_string?.(&1))
)
|> Composite.param(:some_field2, &where(&1, some_field2: ^&2))
|> Repo.all()

However, library can be used not only with Ecto.
For more complex example with joins check test file.

Currently, it is not published to hex and available only on Github
https://github.com/fuelen/composite
Any feedback is welcome!