From 63e35a1323b6a9b7ad7c90217116cdc99a45da1d Mon Sep 17 00:00:00 2001 From: Ryuta Kamizono Date: Sun, 28 May 2017 09:29:49 +0900 Subject: Fix GROUP BY queries to apply LIMIT/OFFSET after aggregations If `eager_loading` is true, `apply_join_dependency` force applies LIMIT/OFFSET before JOINs by `limited_ids_for` to keep parent records count. But for aggregation queries, LIMIT/OFFSET should be applied after aggregations the same as SQL semantics. And also, we could not replace SELECT list by `limited_ids_for` when a query has a GROUP BY clause. It had never been worked since it will causes generating invalid SQL for MySQL, PostgreSQL, and probably most backends. ``` % ARCONN=postgresql be ruby -w -Itest test/cases/calculations_test.rb -n test_group_by_with_limit Using postgresql Run options: -n test_group_by_with_limit --seed 20925 # Running: E Error: CalculationsTest#test_group_by_with_limit: ActiveRecord::StatementInvalid: PG::GroupingError: ERROR: column "posts.id" must appear in the GROUP BY clause or be used in an aggregate function LINE 1: SELECT DISTINCT "posts"."id", "posts"."type" AS alias_0 FRO... ^ : SELECT DISTINCT "posts"."id", "posts"."type" AS alias_0 FROM "posts" LEFT OUTER JOIN "comments" ON "comments"."post_id" = "posts"."id" GROUP BY "posts"."type" ORDER BY "posts"."type" ASC LIMIT $1 ``` Fixes #8103. Closes #27249. --- activerecord/test/cases/calculations_test.rb | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'activerecord/test/cases') diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb index 080d2a54bc..6ceac59eec 100644 --- a/activerecord/test/cases/calculations_test.rb +++ b/activerecord/test/cases/calculations_test.rb @@ -705,6 +705,24 @@ class CalculationsTest < ActiveRecord::TestCase assert_equal [], Topic.includes(:replies).order(:id).offset(5).pluck(:id) end + def test_group_by_with_limit + expected = { "Post" => 8, "SpecialPost" => 1 } + actual = Post.includes(:comments).group(:type).order(:type).limit(2).count("comments.id") + assert_equal expected, actual + end + + def test_group_by_with_offset + expected = { "SpecialPost" => 1, "StiPost" => 2 } + actual = Post.includes(:comments).group(:type).order(:type).offset(1).count("comments.id") + assert_equal expected, actual + end + + def test_group_by_with_limit_and_offset + expected = { "SpecialPost" => 1 } + actual = Post.includes(:comments).group(:type).order(:type).offset(1).limit(1).count("comments.id") + assert_equal expected, actual + end + def test_pluck_not_auto_table_name_prefix_if_column_included Company.create!(name: "test", contracts: [Contract.new(developer_id: 7)]) ids = Company.includes(:contracts).pluck(:developer_id) -- cgit v1.2.3