Question

我有三张桌子;医生，人和约会。医生表：

+-----------+----------+---------+----------------+----------------+
| doctor_id | phone_no | room_no | date_qualified | date_appointed |
+-----------+----------+---------+----------------+----------------+
| 50        | 1234     | 1       | 1963-09-01     | 1991-05-10     |
| 51        | 1235     | 2       | 1973-09-12     | 1991-05-10     |
| 52        | 1236     | 3       | 1990-10-02     | 1993-04-01     |
| 53        | 1237     | 4       | 1965-06-30     | 1994-03-01     |
+-----------+----------+---------+----------------+----------------+

人员表

+-----------+----------+-----------+---------------+------+
| person_id | initials | last_name | date_of_birth | sex  |
+-----------+----------+-----------+---------------+------+
| 100       | T        | Williams  | 1972-01-12    | m    |
| 101       | J        | Garcia    | 1981-03-18    | f    |
| 102       | W        | Fisher    | 1950-10-22    | m    |
| 103       | K        | Waldon    | 1942-06-01    | m    |
| 104       | P        | Timms     | 1928-06-03    | m    |
| 105       | A        | Dryden    | 1944-06-23    | m    |
| 106       | F        | Fogg      | 1955-10-16    | f    |
| 150       | T        | Saj       | 1994-06-17    | m    |
| 50        | A        | Cameron   | 1937-04-04    | m    |
| 51        | B        | Finlay    | 1948-12-01    | m    |
| 52        | C        | King      | 1965-06-06    | f    |
| 53        | D        | Waldon    | 1938-07-08    | f    |
+-----------+----------+-----------+---------------+------+

约会表

+-----------+------------+------------+-----------+---------------+
| doctor_id | patient_id | appt_date  | appt_time | appt_duration |
+-----------+------------+------------+-----------+---------------+
| 50        | 100        | 1994-08-10 | 10:00:00  |            10 |
| 50        | 100        | 1994-08-16 | 10:50:00  |            10 |
| 50        | 102        | 1994-08-21 | 11:20:00  |            20 |
| 50        | 103        | 1994-08-10 | 10:10:00  |            10 |
| 50        | 104        | 1994-08-10 | 10:20:00  |            20 |
| 52        | 102        | 1994-08-10 | 10:00:00  |            10 |
| 52        | 105        | 1994-08-10 | 10:10:00  |            10 |
| 52        | 150        | 2014-03-10 | 12:00:00  |            15 |
| 53        | 106        | 1994-08-10 | 11:30:00  |            10 |
+-----------+------------+------------+-----------+---------------+

我需要创建一个查询来生成一个doctor IDs列表及其名称及其约会数。

我已经创建了一个声明来生成医生ID列表，其中包含他们的约会数量，但我不确定如何生成包含医生ID及其姓名的列表。

我现在的陈述是：

select doctor.doctor_id, count(appointment.appt_time) as no_appt
from doctor
left join appointment
on doctor.doctor_id = appointment.doctor_id
group by doctor.doctor_id;

请帮助。

Answer 1

您需要额外加入person表。显然，doctor_id是链接。呸。这应该是一个显式列，而不是重用id。

select d.doctor_id, p.initials, p.last_name, count(appointment.appt_time) as no_appt
from doctor d left join
     appointment a
     on d.doctor_id = a.doctor_id left join
     person p
     on d.doctor_id = p.person_id
group by d.doctor_id, p.initials, p.last_name;

在MySQL中，您实际上不需要将两列添加到group by，但最好这样做。

Answer 2

select doctor.doctor_id, person.initials, person.last_name, count(appointment.appt_time) as no_appt
from doctor 
left join appointment on doctor.doctor_id = appointment.doctor_id
left join person on person.person_id = appointment.patient_id 
group by doctor.doctor_id;

Answer 3

你的SQL几乎就在那里 - 你只需要在Person表中添加一个JOIN来获取医生的初始和最后一个名字 - 就像这样：

SELECT 
    d.doctor_id, 
    p.initials,
    p.last_name,
    COUNT(a.*)
FROM [person] p
JOIN [doctor] d ON p.person_id = d.doctor_id
LEFT JOIN [appointment] a ON a.doctor_id = d.doctor_id
GROUP BY d.doctor_id, p.initials, p.last_name

希望这有帮助

SQL数据库 - 查询以生成医生ID列表及其名称及其约会数量？

3 个答案: