JOIN中的多个ON子句

Question

ON中是否可以有两个JOIN语句？

我有两个表：

+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| product_id    | int     |
| start_date    | date    |
| end_date      | date    |
| price         | int     |
+---------------+---------+

+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| product_id    | int     |
| purchase_date | date    |
| units         | int     |
+---------------+---------+

[制作JOIN时，我写：ON table1.product_id=table2.product_id。但是，如何添加purchase_date也在start_date和end_date之间的子句。当我使用WHERE语句时，我找不到正确的答案。

Answer 1

您可以在ON子句中添加多个条件

SELECT table1.*, table2.*
FROM table1
LEFT JOIN table2
  ON table1.product_id = table2.product_id
  AND table2.purchase_date >= table1.start_date
  AND table2.purchase_date <= table1.end_date
-- ADD WHERE CLAUSE HERE IF NEEDED