Mysql按基本价格或折扣值排序（如果不为空）

我想按价格对数据进行排序。但我有两列数据表，即基本价格和折扣值。我想通过比较它来排序，如果有折扣值，那么小的值将被排序。但在这个问题中，我只能根据折扣值或基本价格进行排序，而不能将两者结合起来。有办法克服它吗

查询：

结果:

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将订单条款更改为以下内容：

ORDER BY IFNULL(pd.discount_value, p.base_price) ASC

以下是修改后的查询的外观：

select `p`.`id`, `p`.`name`, `p`.`product_code`, `p`.`base_price`, `pd`.`discount_value`, `p`.`weight`, `c`.`category`, pc.id as product_color_id, `pc`.`base_color`, `i`.`image`, sum(ps.stock) as stock, `p`.`status` from `products` as `p` 
left join `category_product` as `cp` on `p`.`id` = `cp`.`product_id` 
left join `categories` as `c` on `cp`.`category_id` = `c`.`id` 
left join `product_colors` as `pc` on `p`.`id` = `pc`.`product_id` 
left join `image_product_color` as `ipc` on `ipc`.`id` = (select ipc1.id from image_product_color as ipc1 where pc.id = ipc1.product_color_id order by ipc1.id desc limit 1) 
left join `images` as `i` on `i`.`id` = (select i1.id from images as i1 where ipc.image_id = i1.id order by i1.id desc limit 1) 
left join `product_sizes` as `ps` on `pc`.`id` = `ps`.`product_color_id` 
left join `product_discounts` as `pd` on `pd`.`id` = (select pd1.id from product_discounts as pd1 where p.id = pd1.product_id and date(now()) <= pd1.valid_until) 
group by `p`.`id`, `p`.`name`, `p`.`product_code`, `p`.`base_price`, `pd`.`discount_value`, `p`.`weight`, `c`.`category`, `pc`.`id`, `pc`.`base_color`, `i`.`image`, `p`.`status` 
ORDER BY IFNULL(pd.discount_value, p.base_price) ASC;

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尝试按IFNULLpd订购。折扣价格，p.base价格作为其工作感谢broI已将其作为答案，请接受并投票：

select `p`.`id`, `p`.`name`, `p`.`product_code`, `p`.`base_price`, `pd`.`discount_value`, `p`.`weight`, `c`.`category`, pc.id as product_color_id, `pc`.`base_color`, `i`.`image`, sum(ps.stock) as stock, `p`.`status` from `products` as `p` 
left join `category_product` as `cp` on `p`.`id` = `cp`.`product_id` 
left join `categories` as `c` on `cp`.`category_id` = `c`.`id` 
left join `product_colors` as `pc` on `p`.`id` = `pc`.`product_id` 
left join `image_product_color` as `ipc` on `ipc`.`id` = (select ipc1.id from image_product_color as ipc1 where pc.id = ipc1.product_color_id order by ipc1.id desc limit 1) 
left join `images` as `i` on `i`.`id` = (select i1.id from images as i1 where ipc.image_id = i1.id order by i1.id desc limit 1) 
left join `product_sizes` as `ps` on `pc`.`id` = `ps`.`product_color_id` 
left join `product_discounts` as `pd` on `pd`.`id` = (select pd1.id from product_discounts as pd1 where p.id = pd1.product_id and date(now()) <= pd1.valid_until) 
group by `p`.`id`, `p`.`name`, `p`.`product_code`, `p`.`base_price`, `pd`.`discount_value`, `p`.`weight`, `c`.`category`, `pc`.`id`, `pc`.`base_color`, `i`.`image`, `p`.`status` 
ORDER BY IFNULL(pd.discount_value, p.base_price) ASC;