fix sql join of user's votes

An inner join only returns the comments the user has voted on (not useful for the Unread page in particular). A left join on comment_id or user_id returns duplicate rows (any 'outer apply' is nonstandard). So this just subselects it.
lobsters · Feb 1, 2018 · 0b5567629961df60686e7c807930b796ad2f38dc · 0b55676
1 parent b220c0d
commit 0b5567629961df60686e7c807930b796ad2f38dc
Unified Split

Showing with 41 additions and 2 deletions.

+1 −0 app/controllers/replies_controller.rb

+5 −0 db/migrate/20180201172618_update_replying_comments_to_version_5.rb

+2 −2 db/schema.rb

+33 −0 db/views/replying_comments_v05.sql
diff --git a/app/controllers/replies_controller.rb b/app/controllers/replies_controller.rb
@@ -47,6 +47,7 @@ def unread
  # with the current user's vote added by StoriesController.load_user_votes
  def apply_current_vote
    @replies.each do |r|
+      next unless r.current_vote_vote.present?
      r.comment.current_vote = {
        vote: r.current_vote_vote,
        reason: r.current_vote_reason.to_s
diff --git a/db/migrate/20180201172618_update_replying_comments_to_version_5.rb b/db/migrate/20180201172618_update_replying_comments_to_version_5.rb
@@ -0,0 +1,5 @@
+class UpdateReplyingCommentsToVersion5 < ActiveRecord::Migration[5.0]
+  def change
+    update_view :replying_comments, version: 5, revert_to_version: 4
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.

-ActiveRecord::Schema.define(version: 20180201041055) do
+ActiveRecord::Schema.define(version: 20180201172618) do

  create_table "comments", id: :integer, unsigned: true, force: :cascade, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4" do |t|
    t.datetime "created_at", null: false
@@ -248,7 +248,7 @@


  create_view "replying_comments",  sql_definition: <<-SQL
-      select `lobsters`.`read_ribbons`.`user_id` AS `user_id`,`lobsters`.`comments`.`id` AS `comment_id`,`lobsters`.`read_ribbons`.`story_id` AS `story_id`,`lobsters`.`comments`.`parent_comment_id` AS `parent_comment_id`,`lobsters`.`comments`.`created_at` AS `comment_created_at`,`parent_comments`.`user_id` AS `parent_comment_author_id`,`lobsters`.`comments`.`user_id` AS `comment_author_id`,`lobsters`.`stories`.`user_id` AS `story_author_id`,(`lobsters`.`read_ribbons`.`updated_at` < `lobsters`.`comments`.`created_at`) AS `is_unread`,`lobsters`.`votes`.`vote` AS `current_vote_vote`,`lobsters`.`votes`.`reason` AS `current_vote_reason` from ((((`lobsters`.`read_ribbons` join `lobsters`.`comments` on((`lobsters`.`comments`.`story_id` = `lobsters`.`read_ribbons`.`story_id`))) join `lobsters`.`votes` on((`lobsters`.`votes`.`comment_id` = `lobsters`.`comments`.`id`))) join `lobsters`.`stories` on((`lobsters`.`stories`.`id` = `lobsters`.`comments`.`story_id`))) left join `lobsters`.`comments` `parent_comments` on((`parent_comments`.`id` = `lobsters`.`comments`.`parent_comment_id`))) where ((`lobsters`.`read_ribbons`.`is_following` = 1) and (`lobsters`.`comments`.`user_id` <> `lobsters`.`read_ribbons`.`user_id`) and (`lobsters`.`votes`.`user_id` = `lobsters`.`read_ribbons`.`user_id`) and ((`parent_comments`.`user_id` = `lobsters`.`read_ribbons`.`user_id`) or (isnull(`parent_comments`.`user_id`) and (`lobsters`.`stories`.`user_id` = `lobsters`.`read_ribbons`.`user_id`))) and ((`lobsters`.`comments`.`upvotes` - `lobsters`.`comments`.`downvotes`) >= 0) and (isnull(`parent_comments`.`id`) or ((`parent_comments`.`upvotes` - `parent_comments`.`downvotes`) >= 0)))
+      select `lobsters`.`read_ribbons`.`user_id` AS `user_id`,`lobsters`.`comments`.`id` AS `comment_id`,`lobsters`.`read_ribbons`.`story_id` AS `story_id`,`lobsters`.`comments`.`parent_comment_id` AS `parent_comment_id`,`lobsters`.`comments`.`created_at` AS `comment_created_at`,`parent_comments`.`user_id` AS `parent_comment_author_id`,`lobsters`.`comments`.`user_id` AS `comment_author_id`,`lobsters`.`stories`.`user_id` AS `story_author_id`,(`lobsters`.`read_ribbons`.`updated_at` < `lobsters`.`comments`.`created_at`) AS `is_unread`,(select `lobsters`.`votes`.`vote` from `lobsters`.`votes` where ((`lobsters`.`votes`.`user_id` = `lobsters`.`read_ribbons`.`user_id`) and (`lobsters`.`votes`.`comment_id` = `lobsters`.`comments`.`id`))) AS `current_vote_vote`,(select `lobsters`.`votes`.`reason` from `lobsters`.`votes` where ((`lobsters`.`votes`.`user_id` = `lobsters`.`read_ribbons`.`user_id`) and (`lobsters`.`votes`.`comment_id` = `lobsters`.`comments`.`id`))) AS `current_vote_reason` from (((`lobsters`.`read_ribbons` join `lobsters`.`comments` on((`lobsters`.`comments`.`story_id` = `lobsters`.`read_ribbons`.`story_id`))) join `lobsters`.`stories` on((`lobsters`.`stories`.`id` = `lobsters`.`comments`.`story_id`))) left join `lobsters`.`comments` `parent_comments` on((`parent_comments`.`id` = `lobsters`.`comments`.`parent_comment_id`))) where ((`lobsters`.`read_ribbons`.`is_following` = 1) and (`lobsters`.`comments`.`user_id` <> `lobsters`.`read_ribbons`.`user_id`) and ((`parent_comments`.`user_id` = `lobsters`.`read_ribbons`.`user_id`) or (isnull(`parent_comments`.`user_id`) and (`lobsters`.`stories`.`user_id` = `lobsters`.`read_ribbons`.`user_id`))) and ((`lobsters`.`comments`.`upvotes` - `lobsters`.`comments`.`downvotes`) >= 0) and (isnull(`parent_comments`.`id`) or ((`parent_comments`.`upvotes` - `parent_comments`.`downvotes`) >= 0)))
  SQL

 end
diff --git a/db/views/replying_comments_v05.sql b/db/views/replying_comments_v05.sql
@@ -0,0 +1,33 @@
+SELECT
+    read_ribbons.user_id,
+    comments.id as comment_id,
+    read_ribbons.story_id as story_id,
+    comments.parent_comment_id,
+    comments.created_at as comment_created_at,
+    parent_comments.user_id as parent_comment_author_id,
+    comments.user_id as comment_author_id,
+    stories.user_id as story_author_id,
+    (read_ribbons.updated_at < comments.created_at) as is_unread,
+    (select votes.vote from votes where votes.user_id = read_ribbons.user_id and votes.comment_id = comments.id) as current_vote_vote,
+    (select votes.reason from votes where votes.user_id = read_ribbons.user_id and votes.comment_id = comments.id) as current_vote_reason
+FROM
+    read_ribbons
+JOIN
+    comments ON comments.story_id = read_ribbons.story_id
+JOIN
+    stories ON stories.id = comments.story_id
+LEFT JOIN
+    comments parent_comments ON parent_comments.id = comments.parent_comment_id
+WHERE
+    read_ribbons.is_following = 1
+    AND comments.user_id != read_ribbons.user_id
+    AND
+        (parent_comments.user_id = read_ribbons.user_id
+         OR (parent_comments.user_id IS NULL
+         AND stories.user_id = read_ribbons.user_id))
+    AND (comments.upvotes - comments.downvotes) >= 0
+    AND (
+      parent_comments.id IS NULL
+      OR (parent_comments.upvotes - parent_comments.downvotes) >= 0
+    )
+;