# 1795. 每个产品在不同商店的价格

### Link

{% embed url="<https://leetcode.cn/problems/rearrange-products-table/>" %}

### Problem

请你重构 Products 表，查询每个产品在不同商店的价格，使得输出的格式变为(product\_id, store, price) 。如果这一产品在商店里没有出售，则不输出这一行。

输出结果表中的 顺序不作要求 。

查询输出格式请参考下面示例。

示例 1：

{% code overflow="wrap" %}

```
输入：
Products table:
+------------+--------+--------+--------+
| product_id | store1 | store2 | store3 |
+------------+--------+--------+--------+
| 0          | 95     | 100    | 105    |
| 1          | 70     | null   | 80     |
+------------+--------+--------+--------+
输出：
+------------+--------+-------+
| product_id | store  | price |
+------------+--------+-------+
| 0          | store1 | 95    |
| 0          | store2 | 100   |
| 0          | store3 | 105   |
| 1          | store1 | 70    |
| 1          | store3 | 80    |
+------------+--------+-------+
解释：
产品0在store1，store2,store3的价格分别为95,100,105。
产品1在store1，store3的价格分别为70,80。在store2无法买到。
```

{% endcode %}

### Solution

{% tabs %}
{% tab title="MySQL" %}

```sql
# Write your MySQL query statement below
select product_id, 'store1' as store, store1 as price
from Products where store1 is not null
union all 
select product_id, 'store2' as store, store2 as price
from Products where store2 is not null
union all
select product_id, 'store3' as store, store3 as price
from Products where store3 is not null
```

{% endtab %}

{% tab title="Go" %}

```go
```

{% endtab %}
{% endtabs %}