在 PostgreSQL JSONB 列中的对象数组中按日期搜索

Question

我的 PostgreSQL 9.6 实例中有两个表。

users

+----+------------+-----------+-------------------+
| id | first_name | last_name | email             |
+----+------------+-----------+-------------------+
| 1  | John       | Doe       | john.doe@test.com |
+----+------------+-----------+-------------------+
| 2  | Jane       | Doe       | jane.doe@test.com |
+----+------------+-----------+-------------------+
| 3  | Mike       | Doe       | mike.doe@test.com |
+----+------------+-----------+-------------------+


surveys
+----+---------+----------------------------------------------------------------------------------------------------+
| id | user_id | survey_data                                                                                        |
+----+---------+----------------------------------------------------------------------------------------------------+
| 1  | 1       | {'child_list': [{'gender': 1, 'birthday': '2015-10-01'}, {'gender': 2, 'birthday': '2017-05-01'}]} |
+----+---------+----------------------------------------------------------------------------------------------------+
| 2  | 2       | {'child_list': []}                                                                                 |
+----+---------+----------------------------------------------------------------------------------------------------+
| 3  | 3       | {'child_list': [{'gender': 2, 'birthday': '2008-01-01'}]}                                          |
+----+---------+----------------------------------------------------------------------------------------------------+

我希望能够查询这两个表以获取在特定年龄之间有孩子的用户数量。 该survey_data列surveys表是JSONB列。

到目前为止，我已经尝试将jsonb_populate_recordset与LATERAL连接一起使用。 我能够将child_list数组SELECT为两列，但无法弄清楚如何在users和surveys表之间使用我的JOIN 。 我使用的查询如下：

SELECT DISTINCT u.email
FROM surveys
  CROSS  JOIN LATERAL (
   SELECT *
   FROM  jsonb_populate_recordset(null::json_type, (survey.survey_data->>'child_list')::jsonb) AS d
   ) d
INNER JOIN users u ON u.id = survey.user_id
WHERE d.birthday BETWEEN '2014-05-05' AND '2018-05-05';

这也使用了使用此创建的自定义类型：

CREATE type json_type AS (gender int, birthday date)

我的问题是，有没有更容易阅读的方法来做到这一点？ 我想将此查询与许多其他JOIN和WHERE子句一起使用，我想知道是否有更好的方法来做到这一点。

注意：这主要由不需要超快但当然欢迎任何速度提升的报告系统使用。

Answer 1

使用函数jsonb_array_elements(),示例：

select email, (elem->>'gender')::int as gender, (elem->>'birthday')::date as birthday
from users u
left join surveys s on s.user_id = u.id
cross join jsonb_array_elements(survey_data->'child_list') as arr(elem)

       email       | gender |  birthday  
-------------------+--------+------------
 john.doe@test.com |      1 | 2015-10-01
 john.doe@test.com |      2 | 2017-05-01
 mike.doe@test.com |      2 | 2008-01-01
(3 rows)

或者

select distinct email
from users u
left join surveys s on s.user_id = u.id
cross join jsonb_array_elements(survey_data->'child_list') as arr(elem)
where (elem->>'birthday')::date between '2014-05-05' and '2018-05-05';

       email       
-------------------
 john.doe@test.com
(1 row) 

您可以使用视图让您的生活更轻松：

create view users_children as
    select email, (elem->>'gender')::int as gender, (elem->>'birthday')::date as birthday
    from users u
    left join surveys s on s.user_id = u.id
    cross join jsonb_array_elements(survey_data->'child_list') as arr(elem);

select distinct email
from users_children
where birthday between '2014-05-05' and '2018-05-05';