SQL INNER JOIN 多个表和列

Question

问题：

Construct the SQL statement to find all of the people that have meetings only before Dec. 25, 2016 at noon using INNER JOINs. Display the following columns:
 Person’s first name
 Person’s last name
 Meeting ID
 Meeting start date and time
 Meeting end date and time

表格： 这个数据库有5个表（person, building, room, meeting, person_meeting

+-----------+------------+------------+
| person_id | first_name | last_name  |
+-----------+------------+------------+
|         1 | Tom        | Hanks      |
|         2 | Anne       | Hathaway   |
|         3 | Tom        | Cruise     |
|         4 | Meryl      | Streep     |
|         5 | Chris      | Pratt      |
|         6 | Halle      | Berry      |
|         7 | Robert     | De Niro    |
|         8 | Julia      | Roberts    |
|         9 | Denzel     | Washington |
|        10 | Melissa    | McCarthy   |
+-----------+------------+------------+

+-------------+----------------------+
| building_id | building_name        |
+-------------+----------------------+
|           1 | Headquarters         |
|           2 | Main Street Buidling |
+-------------+----------------------+

+---------+-------------+-------------+----------+
| room_id | room_number | building_id | capacity |
+---------+-------------+-------------+----------+
|       1 | 100         |           1 |        5 |
|       2 | 200         |           1 |        4 |
|       3 | 300         |           1 |       10 |
|       4 | 10          |           2 |        4 |
|       5 | 20          |           2 |        4 |
+---------+-------------+-------------+----------+

+------------+---------+---------------------+---------------------+
| meeting_id | room_id | meeting_start       | meeting_end         |
+------------+---------+---------------------+---------------------+
|          1 |       1 | 2016-12-25 09:00:00 | 2016-12-25 10:00:00 |
|          2 |       1 | 2016-12-25 10:00:00 | 2016-12-25 12:00:00 |
|          3 |       1 | 2016-12-25 11:00:00 | 2016-12-25 12:00:00 |
|          4 |       2 | 2016-12-25 09:00:00 | 2016-12-25 10:00:00 |
|          5 |       4 | 2016-12-25 09:00:00 | 2016-12-25 10:00:00 |
|          6 |       5 | 2016-12-25 14:00:00 | 2016-12-25 16:00:00 |
+------------+---------+---------------------+---------------------+

+-----------+------------+
| person_id | meeting_id |
+-----------+------------+
|         1 |          1 |
|        10 |          1 |
|         1 |          2 |
|         2 |          2 |
|         3 |          2 |
|         4 |          2 |
|         5 |          2 |
|         6 |          2 |
|         7 |          2 |
|         8 |          2 |
|         9 |          3 |
|        10 |          3 |
|         1 |          4 |
|         2 |          4 |
|         8 |          5 |
|         9 |          5 |
|         1 |          6 |
|         2 |          6 |
|         3 |          6 |
+-----------+------------+

到目前为止我的解决方案：

SELECT first_name,last_name ,building_name,meeting_start,meeting_end 来自 P 人 INNER JOIN B楼 ON P.person_id=PM.person_id INNER JOIN person_meeting PM ON M.room_id

我在完成 SQL 语句时遇到问题，请尽可能提供帮助。

Answer 1

这可能对你有用。我为连接中的每个表使用了别名，并在您需要的列的选择语句中使用了它们。然后我加入了所需的表格，并在 where 中确定了在 12 月 12 日中午之前带有 meeting_end 的表格。 （我假设，如果您想启动它，只需将其切换到 meeting_start）

select p.first_name,p.last_name,pm.meeting_id,m.meeting_start,m.meeting_end from person p
inner join person_meeting pm on pm.person_id = p.person_id
inner join meeting m on m.meeting_id = pm.meeting_id
where m.meeting_end > '2016-12-25 12:00:00'