mysql - mysql连接两个不同的表以列出一个结果

Question

我有两个 MySQL 表：'invoice' 和 'credit_memo'

我想将它们结合起来并列出一个按日期排序的结果。

发票：
ID INT
日期 DATETIME
customer_id INT

credit_memo:
ID INT
日期 DATETIME
customer_id INT

我的最后尝试：

(SELECT ID AS invoice_number FROM invoice)
UNION
(SELECT ID AS credit_memo_number FROM credit_memo)
ORDER BY date

问题是 invoice_number 和 credit_memo_number 都被放入 invoice_number 变量中。因此，当我运行结果时，它看起来像是来自“发票”表。

如何确定每个特定行从哪个表中提取？

谢谢你，安迪

Answer 1

select id, t.table_name from invoice join information_schema.tables t on t.table_name='invoice'
union
select id, t.table_name from credit_memo join information_schema.tables t on t.table_name='credit_memo'

Answer 2

以下是您将如何处理它。

这两个表都有客户 ID，因此我们可以通过它加入它们：

SELECT i.ID AS invoice_number,c.ID AS credit_memo_number 
FROM invoice i
JOIN credit_memo c ON c.customer_id = i.customer_id
ORDER BY i.date ASC

这将选择发票 ID 和信用 ID，并按发票日期排序。