ruby-on-rails - 使用 ILIKE 查询时的 PostgreSQL 优先级

Question

两个固定装置:

one:
  firstname: John
  lastname: Doe
  user_id: 1

two:
  firstname: Jane
  lastname: Doe
  user_id: 1

在我的单元测试中，我有以下内容:

 test "Searching for a contact gets the right person" do
    search = Contact.search("John")
    assert_equal 1, search.count

    search = Contact.search("Doe")
    assert_equal 2, search.count

    search = Contact.search("John Doe")
    assert_equal 1, search.count

    search = Contact.search("John ")
    assert_equal 1, search.count

    search = Contact.search("Doe John")
    assert_equal 1, search.count
  end

...最后是我的模型，它调用搜索方法如下所示:

  def self.search(search)
    # Check if the search query has more than one word
    search_split = search.split(" ")
    if search_split.count > 1
      # User must be searching for a first and last name
      first_word = '%' + search_split[0] + '%'
      second_word = '%' + search_split[1] + '%'
      conditions = "
        firstname ILIKE ? OR lastname ILIKE ? 
        AND 
        firstname ILIKE ? OR lastname ILIKE ?", 
        first_word, first_word, second_word, second_word
      where(conditions)
    else
      # Just searching for a first OR last name
      # Strip any whitespace
      str = search_split[0]
      query = '%' + str + '%'
      conditions = "firstname ILIKE ? OR lastname ILIKE ?", query, query
      where(conditions)
    end
  end

除了对“John Doe”进行测试的测试之外，所有测试都通过了。它实际上最终也拉动了“Jane Doe”。

我认为在相邻的 AND 之前调用两个 OR 存在某种优先级问题，但这对我要完成的事情有意义吗？

我还没有到重构的地步；只是想变绿，这样我才能前进。提前感谢您的帮助!

Answer 1

您需要进行一些重组才能获得您所追求的逻辑:

conditions = "
  (firstname ILIKE ? AND lastname ILIKE ?)
  OR
  (firstname ILIKE ? AND lastname ILIKE ?)",
  first_word, second_word, second_word, first_word

当您调用时，它应该同时匹配“John Doe”和“Doe John”，但不匹配“Jane Doe”:

Contact.search('Jo Do')

您实际上不需要括号，因为 AND has a higher precedence than OR在 bool 代数中(SQL 的逻辑是 based on Boolean Algebra )，但没有充分的理由不包括它们。