如何從彼此相關的三個表中查找信息（MySQL）

Question

我在MySQL創建了一個數據庫經銷商 ，其中包含有關經銷商的所有信息，例如：

     dealer id
     dealer name
     dealer email
     dealer phone no
     dealer's primary address
     dealer's billing address
     dealer's contact person
     dealer's contact person's name
     dealer's contact person's email

並且此信息存儲在三個表中，即：

    dealer
    address
    contact_person

表的字段和數據如下：

該表的發牌人將Dealer_id作為主鍵。

    `mysql> select * from dealer;
    +-----------+-------------+----------------+-----------------+
    | dealer_id | dealer_name | dealer_email   | dealer_phone_no |
    +-----------+-------------+----------------+-----------------+
    |       101 | dell        | dell@gmail.com |      9000000000 |
    |       102 | asus        | asus@gmail.com |      8000000000 |
    |       103 | hp          | hp@gmail.com   |      7000000000 |
    +-----------+-------------+----------------+-----------------+
    3 rows in set (0.02 sec)
    `

該表地址具有字段Dealer_address_id作為主鍵，以及字段add_dealer_id作為外鍵，它引用表經銷商的字段Dealer_id 。

    `mysql> select * from address;
    +-------------------+---------------+----------------------+-------------+----------------+
    | dealer_address_id | add_dealer_id | add_line1            |  city       |   address_type |
    +-------------------+---------------+----------------------+-------------+----------------+
    |             10001 |           101 | 1, Dell Avenue       | Round Rock  | Primary        |
    |             10002 |           101 | 1, Dell Avenue       | Round Rock  |  Billing       |
    |             10003 |           102 | 1, Asus Computer     | Fremont     |  Primary       |
    |             10004 |           102 | 1, Asus Headquarters | Taipei      | Billing        |
    |             10005 |           103 | HP Inc               | Palo Alto   |  Primary       |
    |             10006 |           103 | HP Inc               | Bristol     |  Billing       |
    +-------------------+---------------+----------------------+-------------+----------------+
    6 rows in set (0.01 sec)
    `

並且此表contact_person的字段contact_person_id為主鍵，而cp_dealer_id字段為外鍵，該表還引用了發牌人的字段Dealer_id 。

    `mysql> select * from contact_person;
    +-------------------+--------------+-----------------+------------------------+
    | contact_person_id | cp_dealer_id | con_per_name    | con_per_email          | 
    +-------------------+--------------+-----------------+------------------------+
    |              1001 |          101 | Michael S. Dell | michael.dell@gmail.com |       
    |              1002 |          101 | Sam Greenblatt  | sam.dell@gmail.com     |      
    |              1003 |          102 | Jerry Shen      | jerry.asus@gmail.com   |     
    |              1004 |          103 | Dion J. Weisler | dion.hp@gmail.com      |      
    +-------------------+--------------+-----------------+------------------------+
    4 rows in set (0.01 sec)`

我想查找有關經銷商的所有信息，例如：

    dealer id
     dealer name
     dealer email
     dealer phone no
     dealer's primary address
     dealer's billing address
     dealer's contact person
     dealer's contact person's name
     dealer's contact person's email

例如我有查詢：

    `Find dealer on the basis of dealer id `

    `Find dealer on the basis of dealer name `

    `Find dealer on the basis of dealer email `

因此，請幫助我該怎么做？

Answer 1

您正在尋找的是MySQL中的join語句。

這是一個例子：

SELECT Dealer.dealer_id, Dealer.Name, Dealer.Email
FROM Dealer
INNER JOIN Address
ON Dealer.dealer_id=Address.dealer_id;