更新一个table中一个字段的所有记录，其值仅在另一个table中

Question

我有table答：

+---------------+------------+-------+-------------+
| name          | id_product | price | price_medium|
+---------------+------------+-------+-------------+
| phone         |         1  |   300 |         300 |
| mouse         |         2  |    50 |          75 |
| phone         |         1  |   250 |         300 |
| keyboard      |         3  |   100 |         100 |
| mouse         |         2  |   100 |          75 |
| phone         |         1  |   350 |         300 |
+---------------+------------+------+--------------+

在table中，B 是临时的table，每次购买时都会添加产品，然后删除。发送后，我想在 table A 中更新 table B 中的列 "price_medium"，其 product_id 是加法。

+---------------+------------+-------+-------------+
| name          | id_product | price | price_medium|
+---------------+------------+-------+-------------+
| phone         |         1  |   100 |         220 |
| mouse         |         2  |   125 |          92 |
| phone         |         1  |   100 |         220 |
+---------------+------------+------+--------------+

最后的结果会是 table A

+---------------+------------+-------+-------------+
| name          | id_product | price | price_medium|
+---------------+------------+-------+-------------+
| phone         |         1  |   300 |         220 |
| mouse         |         2  |    50 |          92 |
| phone         |         1  |   250 |         220 |
| keyboard      |         3  |   100 |         100 |
| mouse         |         2  |   100 |          92 |
| phone         |         1  |   350 |         220 |
+---------------+------------+------+--------------+

Answer 1

您可以使用 id_product

Inner Join

使用Set更新表A中的price_medium（等于表B中的price_medium）

尝试：

UPDATE tableA AS tA
JOIN tableB AS tB ON tB.id_product = tA.id_product 
SET tA.price_medium = tB.price_medium

更新一个table中一个字段的所有记录，其值仅在另一个table中

Update all the records of a field in a table whose value is only in another table

mysql

record