我想找到一个用户的所有 convos哪里没有 connect
我有一个 convos表，带有 sender_id和 recipient_id它们都是对用户 ID 的引用
# app/models/user.rb
has_many :convos, ->(user) {
unscope(:where).where("sender_id = :id OR recipient_id = :id", id: user.id)
}
请注意，convo 可以属于 sender_id 或 receiver_id 的用户。
# app/models/convo.rb
class Convo < ApplicationRecord
belongs_to :sender, :foreign_key => :sender_id, class_name: 'User'
belongs_to :recipient, :foreign_key => :recipient_id, class_name: 'User'
has_many :msgs, dependent: :destroy
validates_uniqueness_of :sender_id, :scope => :recipient_id
scope :involving, -> (user) do
where("convos.sender_id =? OR convos.recipient_id =?",user.id,user.id)
end
scope :between, -> (sender_id,recipient_id) do
where("(convos.sender_id = ? AND convos.recipient_id =?) OR (convos.sender_id = ? AND convos.recipient_id =?)", sender_id,recipient_id, recipient_id, sender_id)
end
end
Connect table 上有一个 requestor_id和 requestee_id它们都是对用户 ID 的引用。连接模型
class Connect < ApplicationRecord
belongs_to :requestor, :foreign_key => :requestor_id, class_name: 'User'
belongs_to :requestee, :foreign_key => :requestee_id, class_name: 'User'
scope :between, -> (requestor_id,requestee_id) do
where("(connects.requestor_id = ? AND connects.requestee_id =?) OR (connects.requestor_id = ? AND connects.requestee_id =?)", requestor_id,requestee_id, requestee_id, requestor_id)
end
end
我想找到一个用户的所有
convos哪里没有 connect我试过这样的事情:
user = User.first
user.convos.where.not(Connect.between(self.requestor_id, self.requestee_id).length > 0 )
# NoMethodError (undefined method `requestor_id' for main:Object)
user.convos.where.not(Connect.between(convo.requestor_id, convo.requestee_id).length > 0 )
# undefined local variable or method `convo' for main:Object
然后我尝试完全不引用用户，只是尝试在没有连接的情况下获取所有 convos。
Convo.where("Connect.between(? ,?) < ?)", :sender_id, :recipient_id, 1)
# ActiveRecord::StatementInvalid (SQLite3::SQLException: near "between": syntax error: SELECT "convos".* FROM "convos" WHERE (Connect.between('sender_id' ,'recipient_id') < 1)))
Convo.where("Connect.between(? ,?) < ?)", self.sender_id, self.recipient_id, 1)
# NoMethodError (undefined method `sender_id' for main:Object)
在不存在连接的情况下获取所有用户的对话的最佳方法是什么？
更新
这有效，并且是我正在寻找的，但显然这是无用的，我想了解如何在 1 个电话中获得此信息。
@og_connections = []
current_user.convos.each do |convo|
if Connect.between(convo.sender_id, convo.recipient_id).length === 0
@og_connections.push(current_user.id === convo.sender_id ? convo.recipient_id : convo.sender_id)
end
end
@connections = User.select(:id, :first_name, :slug).where(id: @og_connections, status: 'Active')
最佳答案
您可以使用 LEFT JOIN获取在 id 之间匹配的用户行和 convos.sender_id和 convos.recipient_id不是 NULL ，但它们之间的匹配connections.requester_id和 connections.requestee_id是 NULL :
SELECT *
FROM users
LEFT JOIN connects
ON users.id IN (connects.requester_id, connects.requestee_id)
LEFT JOIN convos
ON users.id IN (convos.sender_id, convos.recipient_id)
WHERE connects.requester_id IS NULL AND
connects.requestee_id IS NULL AND
convos.sender_id IS NOT NULL AND
convos.recipient_id IS NOT NULL
AR实现:
User.joins('LEFT JOIN connects ON users.id IN (connects.requester_id, connects.requestee_id)
LEFT JOIN convos ON users.id IN (convos.sender_id, convos.recipient_id)')
.where(connects: { requester_id: nil, requestee_id: nil })
.where.not(convos: { sender_id: nil, recipient_id: nil })
考虑这样的数据库结构:
db=# \d+ users
Table "public.users"
Column | Type | Collation | Nullable | Default | Storage | Stats target | Description
------------+--------------------------------+-----------+----------+-----------------------------------+----------+--------------+-------------
id | bigint | | not null | nextval('users_id_seq'::regclass) | plain | |
name | character varying | | | | extended | |
created_at | timestamp(6) without time zone | | not null | | plain | |
updated_at | timestamp(6) without time zone | | not null | | plain | |
Indexes:
"users_pkey" PRIMARY KEY, btree (id)
db=# \d+ convos
Table "public.convos"
Column | Type | Collation | Nullable | Default | Storage | Stats target | Description
--------------+--------------------------------+-----------+----------+------------------------------------+---------+--------------+-------------
id | bigint | | not null | nextval('convos_id_seq'::regclass) | plain | |
sender_id | integer | | | | plain | |
recipient_id | integer | | | | plain | |
created_at | timestamp(6) without time zone | | not null | | plain | |
updated_at | timestamp(6) without time zone | | not null | | plain | |
Indexes:
"convos_pkey" PRIMARY KEY, btree (id)
db=# \d+ connects
Table "public.connects"
Column | Type | Collation | Nullable | Default | Storage | Stats target | Description
--------------+--------------------------------+-----------+----------+--------------------------------------+---------+--------------+-------------
id | bigint | | not null | nextval('connects_id_seq'::regclass) | plain | |
requestor_id | integer | | | | plain | |
requestee_id | integer | | | | plain | |
created_at | timestamp(6) without time zone | | not null | | plain | |
updated_at | timestamp(6) without time zone | | not null | | plain | |
Indexes:
"connects_pkey" PRIMARY KEY, btree (id)
有以下记录:
db=# select * from users;
id | name | created_at | updated_at
----+------+----------------------------+----------------------------
1 | seb | 2019-11-27 09:59:53.762911 | 2019-11-27 09:59:53.762911
2 | sab | 2019-11-27 09:59:55.455096 | 2019-11-27 09:59:55.455096
3 | foo | 2019-11-27 10:07:19.760675 | 2019-11-27 10:07:19.760675
4 | bar | 2019-11-27 10:07:36.18696 | 2019-11-27 10:07:36.18696
5 | meh | 2019-11-27 10:07:38.465841 | 2019-11-27 10:07:38.465841
(5 rows)
db=# select * from convos;
id | sender_id | recipient_id | created_at | updated_at
----+-----------+--------------+----------------------------+----------------------------
1 | 1 | 2 | 2019-11-27 10:09:36.742426 | 2019-11-27 10:09:36.742426
2 | 1 | 3 | 2019-11-27 10:09:40.555118 | 2019-11-27 10:09:40.555118
(2 rows)
db=# select * from connects;
id | requestor_id | requestee_id | created_at | updated_at
----+--------------+--------------+----------------------------+----------------------------
1 | 1 | 2 | 2019-11-27 10:07:07.76146 | 2019-11-27 10:07:07.76146
2 | 2 | 1 | 2019-11-27 10:07:11.380084 | 2019-11-27 10:07:11.380084
3 | 1 | 4 | 2019-11-27 10:07:47.892944 | 2019-11-27 10:07:47.892944
4 | 5 | 1 | 2019-11-27 10:07:51.406224 | 2019-11-27 10:07:51.406224
(4 rows)
以下查询将仅返回第二个 convo，因为 id 为 3 的用户没有任何连接。
SELECT convos.*
FROM convos
LEFT JOIN users
ON users.id IN (convos.sender_id, convos.recipient_id)
LEFT JOIN connects
ON users.id IN (connects.requestor_id, connects.requestee_id)
WHERE connects.requestor_id IS NULL AND connects.requestee_id IS NULL
id | sender_id | recipient_id | created_at | updated_at | id | name | created_at | updated_at | id | requestor_id | requestee_id | created_at | updated_at
----+-----------+--------------+----------------------------+----------------------------+----+------+----------------------------+----------------------------+----+--------------+--------------+------------+------------
2 | 1 | 3 | 2019-11-27 10:09:40.555118 | 2019-11-27 10:09:40.555118 | 3 | foo | 2019-11-27 10:07:19.760675 | 2019-11-27 10:07:19.760675 | | | | |
(1 row)
Rails 查询可以是这样的:
Convo
.joins('LEFT JOIN users ON users.id IN (convos.sender_id, convos.recipient_id)
LEFT JOIN connects ON users.id IN (connects.requestor_id, connects.requestee_id)')
.where(connects: { requestor_id: nil, requestee_id: nil })
关于ruby-on-rails - Rails 查询，基于来自不相关模型的范围，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/58923030/