I'm trying to do a query that fetches the user_posts table and the respective associations upvotes, downvotes and comments. And I tried like this:
popular_posts =
from(s in UserPost,
where: s.inserted_at >= ^Timex.beginning_of_month(Timex.now()),
where: s.inserted_at <= ^Timex.end_of_month(Timex.now()),
left_join: downvotes in assoc(s, :downvotes),
left_join: comments in assoc(s, :comments),
left_join: upvotes in assoc(s, :upvotes),
preload: [comments: comments, upvotes: upvotes, downvotes: downvotes],
order_by: fragment("(? * 0.5) + (? * 0.1) - (? * 0.4)", ^map_size(s.upvotes), ^map_size(s.comments), ^map_size(s.downvotes)))
|> Repo.all
But it gives the following warnings and errors:
warning: variable "s" does not exist and is being expanded to "s()", please use parentheses to remove the ambiguity or change the variable name
lib/nethub_api_web/resolvers/content.ex:33
warning: variable "s" does not exist and is being expanded to "s()", please use parentheses to remove the ambiguity or change the variable name
lib/nethub_api_web/resolvers/content.ex:33
warning: variable "args" is unused
lib/nethub_api_web/resolvers/content.ex:93
== Compilation error in file lib/nethub_api_web/resolvers/content.ex ==
** (CompileError) lib/nethub_api_web/resolvers/content.ex:33: undefined function s/0
(stdlib) lists.erl:1338: :lists.foreach/2
(stdlib) erl_eval.erl:670: :erl_eval.do_apply/6
(elixir) lib/kernel/parallel_compiler.ex:198: anonymous fn/4 in Kernel.ParallelCompiler.spawn_workers/6
I tried with changing s with UserPosts but it says that the columns don't exist in the table.
I still don't know why, but when I changed:
preload: [comments: comments, upvotes: upvotes, downvotes: downvotes],
order_by: fragment("(? * 0.5) + (? * 0.1) - (? * 0.4)",
^map_size(s.upvotes), ^map_size(s.comments), ^map_size(s.downvotes)))
to:
preload: [:comments, :upvotes, :downvotes],
order_by: fragment("(? * 0.5) + (? * 0.1) - (? * 0.4)",
^map_size(:upvotes), ^map_size(:comments), ^map_size(:downvotes)))
It worked as expected.