fix: Use left_joins in some places

lib/bdfr_browser/chat.ex

@@ -15,7 +15,7 @@ defmodule BdfrBrowser.Chat do
 
   def listing do
     from(c in __MODULE__,
-      join: m in assoc(c, :messages),
+      left_join: m in assoc(c, :messages),
       select: %{id: c.id, accounts: c.accounts, num_messages: count(m.id), latest_message: max(m.posted_at)},
       order_by: [desc: max(m.posted_at)],
       group_by: c.id

lib/bdfr_browser/importer.ex

@@ -25,11 +25,13 @@ defmodule BdfrBrowser.Importer do
     folders = list_folders(sort: :asc)
 
     for folder <- folders do
-      %Subreddit{name: folder}
+      subreddit = Repo.get_by(Subreddit, name: folder)
-      |> Repo.insert(
+
-        on_conflict: :nothing,
+      if is_nil(subreddit) do
-        conflict_target: :name
+        Repo.insert(%Subreddit{name: folder})
-      )
+      else
+        subreddit
+      end
     end
   end
 

lib/bdfr_browser/post.ex

@@ -37,7 +37,7 @@ defmodule BdfrBrowser.Post do
 
   def during_range(subreddit, start_date, end_date) do
     from(p in __MODULE__,
-      join: c in assoc(p, :comments),
+      left_join: c in assoc(p, :comments),
       select: %{id: p.id, title: p.title, author: p.author, posted_at: p.posted_at, num_comments: count(c.id)},
       where:
         p.subreddit_id == ^subreddit.id and type(p.posted_at, :date) >= ^start_date and
@@ -63,7 +63,7 @@ defmodule BdfrBrowser.Post do
 
   def by_author(author) do
     from(p in __MODULE__,
-      join: c in assoc(p, :comments),
+      left_join: c in assoc(p, :comments),
       join: s in assoc(p, :subreddit),
       select: %{
         id: p.id,