MYSQL ORDER BY 2列

Question

我在 MySQL 中有下表:

----------------------------
| id | price | price_promo |
----------------------------
|  1 |    10 |           0 |
|  2 |     8 |           0 |
|  3 |    10 |           9 |
----------------------------

我有以下查询:

$SQLquery = "SELECT * FROM table ORDER BY price ASC"

如果 price_promo > 0 我只想忽略价格列，以按实际收购价格下订单，并获得此结果:

----------------------------
| id | price | price_promo |
----------------------------
|  1 |    10 |           0 |
|  3 |    10 |           9 |
|  2 |     8 |           0 |
----------------------------

执行此操作需要什么查询？

Answer 1

你可以试试

SELECT * FROM your_table 
ORDER BY
    CASE 
       WHEN price_promo = 0 THEN price
       WHEN price_promo IS NULL then price
       ELSE price_primo
    END

在用户评论后编辑:
如果你想要降序使用这个

SELECT * FROM your_table 
ORDER BY
    CASE 
       WHEN price_promo = 0 THEN price
       WHEN price_promo IS NULL then price
       ELSE price_primo
    END DESC