Question

我在MySQL中有一个数据库，我想迁移它，稍微改变一下表的结构。

我是MySQL的新手，请耐心等待。

我有以下表格：

地址

ADDRESS_ID
地址（例如：55th Street）
ZIP_CODE
城市
国家

CustomersOld

CUSTOMER_ID
名称
billing_address
billing_zip_code
billing_city
billing_country

我想将客户数据迁移到具有以下结构的新表中

CustomersNew

CUSTOMER_ID
billing_address_id（地址表的外键）

所以，我想从表 CustomersOld 中取出4个帐单地址字段并执行此操作：

检查地址表是否包含与帐单邮寄地址字段匹配的记录。

1.1。如果是，则仅返回AddressID。

1.2。如果不是，则创建该记录，并返回AddressID。
将AddressID插入CustomersNew表的address_id字段中。

通常，我使用这个简单的脚本来迁移表：

INSERT INTO CustomersNew
SELECT * FROM CustomersOld

我想我必须执行一些嵌套的SELECT和JOIN：

INSERT INTO CustomersNew
    (customer_id, billing_address_id)
SELECT
    customer_id, 
    -- SELECT/JOIN ... (something like that, in order to get the address_id)
FROM CustomersOld

您可以帮助我为每个客户获取相应的billing_address_id吗？

由于

Answer 1

这需要分两步完成。首先创建所有Addresses条记录：

INSERT INTO Addresses (address, zip_code, city, country)
SELECT DISTINCT billing_address, billing_zip_code, billing_city, billing_country
FROM CustomersOld;

然后通过将此表与CustomersNew

连接，创建所有CustomersOld条记录

INSERT INTO CustomersNew (customer_id, billing_address_id)
SELECT c.customer_id, a.address_id
FROM CustomersOld AS c
JOIN Addresses AS a ON c.billing_address = a.address AND c.billing_zip_code = a.zip_code AND c.billing_city = a.city AND c.billing_country = a.country

Answer 2

我建议你这样

Firts将地址与最后一个CustomerOld地址对齐

insert into Addresses (address, zip_code, city, country )
select billing_address, billing_zip_code, billing_city, billing_country
from CustomerOld
where (billing_address, billing_zip_code, billing_city, billing_country ) not in 
            ( select address, zip_code, city, country
              from Addresses
              )

然后使用创建选择

创建和填充CustomersNew

create table CustomersNew
select a.customer_id, b.address_id
from CustomersOld as a 
inner join Addresses as b  on a.billing_address = b.address
    and a.billing_zip_code = b.zip_code
      and  a.billing_city = b.city
        and a. billing_country = b.country

如何从其他表中获取记录的ID？

2 个答案: