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：此数据库中有5个表（人员，建筑物，房间，会议，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 |
+-----------+------------+

我的解决方案：

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

我在填写SQL语句时遇到问题，请尽可能提供帮助。

Answer 1

这可能适合你。我为连接中的每个表使用了别名，并在所需列的select语句中使用它们。然后我加入了所需的表格，在where中，它在12月12日中午之前决定了meeting_end。（我假设，如果您想要它，请将其切换为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'

SQL INNER JOIN多个表和列

1 个答案: