Ecto.Query.API.merge
You're seeing just the function
merge
, go back to Ecto.Query.API module for more information.
Merges the map on the right over the map on the left.
If the map on the left side is a struct, Ecto will check all of the field on the right previously exist on the left before merging.
from(city in City, select: merge(city, %{virtual_field: "some_value"}))
This function is primarily used by Ecto.Query.select_merge/3
to merge different select clauses.