blob: e816608265b27d1f20f1e2feacdc43a186f80405 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
# frozen_string_literal: true
module FromUnion
extend ActiveSupport::Concern
class_methods do
# Produces a query that uses a FROM to select data using a UNION.
#
# Using a FROM for a UNION has in the past lead to better query plans. As
# such, we generally recommend this pattern instead of using a WHERE IN.
#
# Example:
# users = User.from_union([User.where(id: 1), User.where(id: 2)])
#
# This would produce the following SQL query:
#
# SELECT *
# FROM (
# SELECT *
# FROM users
# WHERE id = 1
#
# UNION
#
# SELECT *
# FROM users
# WHERE id = 2
# ) users;
#
# members - An Array of ActiveRecord::Relation objects to use in the UNION.
#
# remove_duplicates - A boolean indicating if duplicate entries should be
# removed. Defaults to true.
#
# remove_order - A boolean indicating if the order from the relations should be
# removed. Defaults to true.
#
# alias_as - The alias to use for the sub query. Defaults to the name of the
# table of the current model.
# rubocop: disable Gitlab/Union
extend FromSetOperator
define_set_operator Gitlab::SQL::Union
# rubocop: enable Gitlab/Union
end
end
|