Mysql сортировка по base_price или discount_value, если не ноль

Question

Я хочу отсортировать данные по цене. но у меня есть две таблицы данных столбца, а именно base_price и discount_value. Я хочу разобраться, сравнив его, если есть скидка и небольшая стоимость. но в этой задаче я могу сортировать только по discount_value или base_price не объединяет оба. есть ли способ преодолеть это?

Запрос:

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 CASE WHEN pd.discount_value = null THEN p.base_price ELSE pd.discount_value END ASC

Результат:

Answer 1

Измените условие ORDER BY на следующее:

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

Вот как выглядит ваш пересмотренный запрос:

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;