创建具有多个表的视图？

Question

我正在尝试创建一个包含 5 个表的视图，但是在尝试将最后两个表连接在一起时遇到了问题。

这是我当前的 MySQL 查询：

CREATE VIEW s_view AS
    SELECT AC.id, A.id AS account_id, A.name, A.description, A.industry, A.phone_fax, A.phone_office, A.shipping_address_street, A.shipping_address_city, A.shipping_address_state, A.shipping_address_postalcode, A.shipping_address_country, C.id AS contact_id, C.first_name, C.last_name, C.title, C.department, C.phone_home, C.phone_mobile, C.phone_work, C.primary_address_street, C.primary_address_city, C.primary_address_state, C.primary_address_postalcode, C.primary_address_country, EA.Email_address
    FROM ACCOUNTS A
    INNER JOIN ACCOUNTS_CONTACTS AS AC ON A.id = AC.account_id 
    INNER JOIN CONTACTS AS C ON C.id = AC.contact_id 
    INNER JOIN EMAIL_ADDR_BEAN_REL AS ER ON ER.bean_id = A.id
    INNER JOIN EMAIL_ADDRESSES AS EA ON ER.email_address_id = EA.id

我的表格是按以下方式设置的：

帐户（id、first_name、last_name 等）

联系人（身份证、姓名等）

ACCOUNT_CONTACTS（id、account_id、contact_id）

EMAIL_ADDR_BEAN_REL（id、bean_id（与 account_id/contact_id 相同）、email_address_id）

EMAIL_ADDRESSES (email_address_id, email_address)

我遇到的问题是 EMAIL_ADDR_BEAN_REL 表有一个可以引用 account_id 或 contact_id 的 bean_id。因此，当我加入表格时，它只返回帐户电子邮件地址，但是我希望它同时返回帐户电子邮件地址和联系人电子邮件地址？

我感觉这是我加入牌桌的方式有问题，但我不确定如何继续前进？

谢谢！

Answer 1

您可以为 EMAIL_ADDR_BEAN_REL 表设置 2 个单独的别名并适当地引用它（因为您的结构，您还必须添加另一个别名版本的 email_address）：

CREATE VIEW s_view AS
    SELECT AC.id, A.id AS account_id, A.name, A.description, A.industry, 
        A.phone_fax, A.phone_office, A.shipping_address_street, 
        A.shipping_address_city, A.shipping_address_state, 
        A.shipping_address_postalcode, A.shipping_address_country, 
        C.id AS contact_id, C.first_name, C.last_name, C.title, 
        C.department, C.phone_home, C.phone_mobile, C.phone_work, 
        C.primary_address_street, C.primary_address_city, 
        C.primary_address_state, C.primary_address_postalcode, 
        C.primary_address_country, 
        EA.Email_address, 
        EA_C.Email_address AS Email_address_c
    FROM ACCOUNTS A
    INNER JOIN ACCOUNTS_CONTACTS AS AC ON A.id = AC.contact_id 
    INNER JOIN CONTACTS AS C ON C.id = AC.account_id 
    LEFT JOIN EMAIL_ADDR_BEAN_REL AS ER ON ER.bean_id = AC.id
        AND ER.bean_module = 'accounts'
    LEFT JOIN EMAIL_ADDR_BEAN_REL AS ER_C ON ER.bean_id = C.id
        AND ER_C.bean_module = 'contacts'
    LEFT JOIN EMAIL_ADDRESSES AS EA ON ER.email_address_id = EA.id
    LEFT JOIN EMAIL_ADDRESSES AS EA_C ON ER_C.email_address_id = EA_C.id

---

编辑

由于您不必为帐户或联系人设置一行（如果我从上面的 cmets 中正确理解 - 谢谢，@BK435），现在将其设置为 LEFT JOIN。我还添加了bean_module 列的指定（尽管我不确定您使用的是什么代码）。