サブクエリを使用しないMySQLクエリのリライトが可能ですか？

Question

サブクエリを使用せずにこのクエリを書き直すことはできますか？私はこれを思いついたの

SELECT `products`.`id` AS `id`,`products`.`parent_id` AS `parent_id`,`products`.`lft` AS `lft`,`products`.`rght` AS `rght`,`products`.`primary` AS `primary`,`products`.`friendly` AS `friendly`,`products`.`code` AS `code`,`products`.`title` AS `title`,`products`.`meta_description` AS `meta_description`,`products`.`meta_keywords` AS `meta_keywords`,`products`.`name` AS `name`,`products`.`description` AS `description`,`products`.`purchase_price` AS `purchase_price`,`products`.`sale_price` AS `sale_price`,`products`.`tax_code_id` AS `tax_code_id`,`products`.`colour_id` AS `colour_id`,`products`.`size_id` AS `size_id`,`products`.`num_sales` AS `num_sales`,`products`.`showcase` AS `showcase`,`products`.`showcase_image` AS `showcase_image`,`products`.`classic` AS `classic`,`products`.`new_release` AS `new_release`,`products`.`default_colour_id` AS `default_colour_id`,`products`.`deleted` AS `deleted`,`products`.`stock_level` AS `stock_level`,`products`.`hidden` AS `hidden`,`products`.`manufacturer_id` AS `manufacturer_id`,`products`.`created` AS `created`,`products`.`modified` AS `modified` 
from `products` 
where `products`.`id` NOT IN (
    select `parentproduct`.`id` 
     from `orders` 
      join `baskets` on `orders`.`basket_id` = `baskets`.`id` 
      join `basket_items` on `basket_items`.`basket_id` = `baskets`.`id` AND `basket_items`.`deleted` = 0 
      join `products` on `products`.`id` = `basket_items`.`product_id` 
      left join `products` `parentproduct` on `parentproduct`.`id` = `products`.`parent_id` 
     group by `parentproduct`.`id` 
     having count(*) >= 1 
) 
AND products.parent_id IS NULL AND products.deleted = 0 
ORDER BY name ASC 

しかし、それはまだ考慮に同じ製品親のために注文していない製品の子供を取る - それは理にかなっていますか？

SELECT parent_products.id, parent_products.name, orders.id 
FROM products 
LEFT JOIN products parent_products ON products.parent_id = parent_products.id 
LEFT JOIN basket_items ON basket_items.product_id = products.id AND basket_items.deleted = 0 
LEFT JOIN baskets ON baskets.id = basket_items.basket_id 
LEFT JOIN orders ON orders.basket_id = baskets.id 
WHERE orders.id IS NULL 
AND products.deleted = 0 
AND parent_products.id IS NOT NULL 
GROUP BY parent_products.name 
ORDER BY parent_products.name ASC 

Answer 1

このクエリを書き換えるのは正当な理由です。サブクエリをビューに移動し、そのビューに参加することをお勧めします。パフォーマンスが良い選択ははるかに速くなります。

また

、

SELECT `products`.... 
from `products` 
    left join (
     select `parentproduct`.`id` 
      from `orders` 
       join `baskets` on `orders`.`basket_id` = `baskets`.`id` 
       join `basket_items` on `basket_items`.`basket_id` = `baskets`.`id` AND `basket_items`.`deleted` = 0 
       join `products` on `products`.`id` = `basket_items`.`product_id` 
       left join `products` `parentproduct` on `parentproduct`.`id` = `products`.`parent_id` 
      group by `parentproduct`.`id` 
      having count(*) >= 1 
    ) as Counts 
    ON products.id = Counts.id 
    where Counts.id IS NULL AND products.parent_id IS NULL AND products.deleted = 0 
    ORDER BY name ASC 

は、それはまだサブクエリを持っていますが、上記の持っていたようになりましたサブクエリは、製品IDごとに一度だけではなく評価されます。