我有一个具有以下架构的表:
people_stages
id | person_id | stage_id | created
1 | 1 | 1 | 2013-09-01 00:00:00
2 | 1 | 2 | 2013-09-02 00:00:00
3 | 1 | 3 | 2013-09-03 00:00:00
我创建了以下查询来选择按人员分组的最新阶段:
SELECT *
FROM people Person
LEFT JOIN people_stages PersonStage ON PersonStage.person_id = Person.id
WHERE PersonStage.created = (SELECT MAX(people_stages.created) FROM people_stages GROUP BY person_id HAVING person_id = PersonStage.person_id);
但是,如果我尝试按 Person 表中的字段排序,它工作正常:
SELECT *
FROM people Person
LEFT JOIN people_stages PersonStage ON PersonStage.person_id = Person.id
WHERE PersonStage.created = (SELECT MAX(people_stages.created) FROM people_stages GROUP BY person_id HAVING person_id = PersonStage.person_id)
ORDER BY Person.last_name;
它返回 0 个结果。
有人可以提供一些见解吗?
谢谢!
编辑:结构people
+----------------------------+--------------------------------------------------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------------------------+--------------------------------------------------------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| internal_id | varchar(50) | NO | MUL | NULL | |
| public_id | varchar(30) | NO | | NULL | |
| counselor_id | bigint(20) | NO | | NULL | |
| term_id | int(11) | NO | MUL | NULL | |
| program_id | int(11) | NO | | NULL | |
| person_type_id | int(11) | NO | MUL | NULL | |
| first_name | varchar(100) | NO | | NULL | |
| middle_name | varchar(100) | NO | | NULL | |
| last_name | varchar(100) | NO | | NULL | |
| photo_url | varchar(255) | NO | | NULL | |
| gender | enum('m','f','u') | NO | | NULL | |
| date_of_birth | date | NO | | NULL | |
| address | varchar(255) | NO | | NULL | |
| address_apt | varchar(100) | NO | | NULL | |
| address_city | varchar(100) | NO | | NULL | |
| address_state | varchar(100) | NO | | NULL | |
| address_state_intl | varchar(255) | NO | | NULL | |
| address_zip | varchar(25) | NO | | NULL | |
| address_country | varchar(100) | NO | | NULL | |
| address_verified | tinyint(1) | NO | | NULL | |
| address_latitude | varchar(100) | NO | | NULL | |
| address_longitude | varchar(100) | NO | | NULL | |
| address_position | point | NO | MUL | NULL | |
| address_distance | smallint(6) | NO | | NULL | |
| social_facebook | mediumtext | NO | | NULL | |
| social_twitter | varchar(255) | NO | | NULL | |
| social_instagram | varchar(255) | NO | | NULL | |
| phone_cell | varchar(25) | NO | | NULL | |
| phone_cell_clean | varchar(25) | YES | | NULL | |
| phone_work | varchar(25) | NO | | NULL | |
| phone_work_clean | varchar(25) | NO | | NULL | |
| permission_to_text | tinyint(1) | NO | | NULL | |
| permission_to_text_confirm | tinyint(1) | NO | | NULL | |
| phone_home | varchar(25) | NO | | NULL | |
| phone_home_clean | varchar(25) | YES | | NULL | |
| email_address | varchar(255) | NO | | NULL | |
| permission_to_email | tinyint(1) | NO | | NULL | |
| preferred_contact | enum('phone_home','phone_cell','text_cell','email','postal') | NO | | NULL | |
| parent_first_name | varchar(100) | NO | | NULL | |
| parent_last_name | varchar(100) | NO | | NULL | |
| parent_email | varchar(255) | NO | | NULL | |
| hs_name | varchar(255) | NO | | NULL | |
| hs_homeschooled | tinyint(1) | NO | | NULL | |
| hs_ceeb_id | varchar(100) | NO | | NULL | |
| hs_grad_year | varchar(4) | NO | | NULL | |
| coll_name | varchar(255) | NO | | NULL | |
| coll_ceeb_id | varchar(100) | NO | | NULL | |
| coll_major | varchar(255) | NO | | NULL | |
| coll_year | varchar(20) | NO | | NULL | |
| counselor_read | tinyint(1) | NO | | NULL | |
| source | varchar(100) | NO | | NULL | |
| entry_method | varchar(100) | NO | | NULL | |
| erp_processed | tinyint(1) | NO | | NULL | |
| created | datetime | NO | | NULL | |
| modified | datetime | NO | | NULL | |
+----------------------------+--------------------------------------------------------------+------+-----+---------+----------------+