Question

我正在进行内连接（至少我认为这是代码正在做的事情）但我的搜索多次返回相同的结果。我想我的加入有问题。

标签

+------------+--------------+------+-----+---------+----------------+
| Field      | Type         | Null | Key | Default | Extra          |
+------------+--------------+------+-----+---------+----------------+
| id         | int(11)      | NO   | PRI | NULL    | auto_increment |
| name       | varchar(255) | YES  |     | NULL    |                |
| color      | varchar(255) | YES  |     | NULL    |                |
| article_id | int(11)      | YES  | MUL | NULL    |                |
| created_at | datetime     | NO   |     | NULL    |                |
| updated_at | datetime     | NO   |     | NULL    |                |
+------------+--------------+------+-----+---------+----------------+

文章

+------------+--------------+------+-----+---------+----------------+
| Field      | Type         | Null | Key | Default | Extra          |
+------------+--------------+------+-----+---------+----------------+
| id         | int(11)      | NO   | PRI | NULL    | auto_increment |
| title      | varchar(255) | YES  |     | NULL    |                |
| info       | text         | YES  |     | NULL    |                |
| created_at | datetime     | NO   |     | NULL    |                |
| updated_at | datetime     | NO   |     | NULL    |                |
+------------+--------------+------+-----+---------+----------------+

我标记的每篇文章都会根据标记返回多个结果。因此，如果文章有3个标签，则会返回3条记录。即使每篇文章只返回1个？

class Article < ApplicationRecord
  has_many :tags, dependent: :destroy
  validates :title, presence: true

  def self.search(search)
  if search
    joins(:tags).where('title LIKE :search OR tags.name LIKE :search', search: "%#{search}%")
  else
    all
  end
end
end

Answer 1

使用.distinct或.group。从rails 4.0.2开始也有.uniq别名。

示例：

joins(:tags).where('title LIKE :search OR tags.name LIKE :search', search: "%#{search}%").distinct

joins(:tags).where('title LIKE :search OR tags.name LIKE :search', search: "%#{search}%").
group('article_id')

Rails搜索返回重复

1 个答案: