mysql—我有一个相当大的sql查询，它被GROUPBY和ORDERBY语句减慢了速度优化的最佳方法是什么？

优化这个查询的最佳方法是什么？因为它需要12秒才能执行？
很抱歉查询太大了，它几乎不需要groupby和order-by语句就可以立即执行。
我对sql优化还比较陌生，我只编写了一年左右的代码。我没有写这个查询，但我需要修复它。

SELECT
`products`.*,
`product_alternative`.`alternative_product_code`,
`product_alternative`.`id` as `product_alternative_id`,
`vat_rate`.`rate` AS `vat_rate`,
`product_images`.`filename` AS `product_image_file`,
`product_docs`.`filename` AS `product_doc_file`,
`suppliers`.`supplier_code`,
`suppliers`.`name` AS `supplier_name`,
`commission`.`commission` AS `supplier_commission`,
`categories`.`name` AS `category_name`,
`sub_categories`.`name` AS `subcategory_name`,
IF(`products`.`product_doc_id` = 0,
 NULL,
 CONCAT(
"/product-docs/",
`products`.`id`
)) AS `product_doc_url`,IF(`products`.`product_image_id` = 0, NULL, CONCAT(
"/product-images/",
`products`.`id`,
"/original/"
)) AS `original_image_url`,IF(`products`.`product_image_id` = 0, NULL, CONCAT(
"/product-images/",
`products`.`id`,
"/medium/"
)) AS `medium_image_url`,IF(`products`.`product_image_id` = 0, NULL, CONCAT(
"/product-images/",
`products`.`id`,
"/thumb/"
)) AS `thumb_image_url`,CASE
WHEN
    `group_favourite`.`id` IS NOT NULL
    THEN 1 ELSE 0
END
AS `group_favourite`
,CASE
WHEN
    `product_favourite`.`org_id` != 0
    AND `product_favourite`.`org_id` IS NOT NULL
    THEN 1 ELSE 0
END
AS `favourite`
,CASE
WHEN
    `product_favourite`.`org_id` != 0
    AND `product_favourite`.`org_id` IS NOT NULL
    THEN 1 ELSE 0
END
AS `favourite`,
`product_favourite`.`needs_authorisation`,

 IF(`customer_personal_favourite`.`id` IS NOT NULL,1,0) AS `is_personal_favourite`
 FROM
`products` 

LEFT JOIN `vat_rate` ON `products`.`vat_rate_id` = `vat_rate`.`id`
LEFT JOIN `product_images` ON `products`.`product_image_id` = `product_images`.`id`
LEFT JOIN `product_docs` ON `products`.`product_doc_id` = `product_docs`.`id`

LEFT JOIN `orgs` AS `suppliers` ON `products`.`supplier_id` = `suppliers`.`id`

LEFT JOIN `commission` ON
    `suppliers`.`id` = `commission`.`org_id`
    AND `commission`.`status` = 1
    AND DATE(`commission`.`start_date`) <= DATE('2020-07-15')
    AND (
        DATE(`commission`.`end_date`) >= DATE('2020-07-15')
        OR `commission`.`end_date` = '0000-00-00'
    )

LEFT JOIN `categories` AS `categories` ON
    `products`.`category_id` = `categories`.`id`

LEFT JOIN `categories` AS `sub_categories` ON
    `products`.`sub_category_id` = `sub_categories`.`id`

LEFT JOIN `product_attribute_product` ON
    `product_attribute_product`.`product_id` = `products`.`id`
LEFT JOIN `product_alternative` ON
    `product_alternative`.`product_original_id` = `products`.`original_id`
JOIN `orgs` AS `customer` ON
`customer`.`id` IN (320)

LEFT JOIN `product_supplier_account` ON
`product_supplier_account`.`product_id` = `products`.`id`

JOIN `supplier_account` AS `default_supplier_account` ON
`default_supplier_account`.`supplier_id` = `products`.`supplier_id`
AND `default_supplier_account`.`is_default` = 1
AND `default_supplier_account`.`is_deleted` = 0

JOIN `customer_to_supplier` ON
`customer_to_supplier`.`supplier_id` = `products`.`supplier_id`
AND `customer_to_supplier`.`customer_id` IN (`customer`.`id`)
AND `customer_to_supplier`.`allow_access` = 1
AND `customer_to_supplier`.`status` = 1

JOIN `customer_to_supplier_account` ON
    `customer_to_supplier_account`.`customer_to_supplier_id` = `customer_to_supplier`.`id`
    AND (
        `customer_to_supplier_account`.`supplier_account_id` =                                    `product_supplier_account`.`supplier_account_id`
        OR `customer_to_supplier_account`.`supplier_account_id` = `default_supplier_account`.`id`
    )
    AND `customer_to_supplier_account`.`allow_access` = 1
    AND `customer_to_supplier_account`.`is_deleted` = 0
LEFT JOIN `statement_products_categories` ON
`statement_products_categories`.`product_id` = `products`.`original_id`
LEFT JOIN `product_favourite` ON
    `product_favourite`.`product_id` = `products`.`original_id`
    AND `product_favourite`.`org_id` IN (`customer`.`id`)
    LEFT JOIN `group_favourite` AS `group_favourite` ON
`products`.`original_id` = `group_favourite`.`product_id`
AND `group_favourite`.`group_id` IN (37)
LEFT JOIN `budget` AS `category_budget` ON
    `category_budget`.`org_id` IN (`customer`.`id`)
    AND `category_budget`.`budget_type_id` = 1
    AND `category_budget`.`category_id` = `products`.`category_id`
    AND
        `category_budget`.`start_date` <= CURDATE()
        AND (
            `category_budget`.`final_date` >= CURDATE()
            OR `category_budget`.`final_date` IS NULL
        )
LEFT JOIN `budget` AS `supplier_budget` ON
    `supplier_budget`.`org_id` IN (`customer`.`id`)
    AND `supplier_budget`.`budget_type_id` = 3
    AND `supplier_budget`.`supplier_id` = `products`.`supplier_id`
    AND
        `supplier_budget`.`start_date` <= CURDATE()
        AND (
            `supplier_budget`.`final_date` >= CURDATE()
            OR `supplier_budget`.`final_date` IS NULL
        )
LEFT JOIN `budget` AS `product_budget` ON
    `product_budget`.`org_id` IN (`customer`.`id`)
    AND `product_budget`.`budget_type_id` = 2
    AND
        `product_budget`.`start_date` <= CURDATE()
        AND (
            `product_budget`.`final_date` >= CURDATE()
            OR `product_budget`.`final_date` IS NULL
        )
LEFT  JOIN `customer_personal_favourite` ON
`customer_personal_favourite`.`org_id` = `customer`.`id`
AND `customer_personal_favourite`.`product_original_id` = `products`.`original_id`

WHERE
0 OR (1  AND `products`.`status` = 1  AND ((
    `products`.`parent_id` = 0
    OR `products`.`parent_id` IS NULL
)   OR (
    `product_favourite`.`org_id` IS NOT NULL
    AND `product_favourite`.`org_id` != 0
)  )  AND `products`.`id` = `products`.`current_id` )
GROUP BY `products`.`id`
ORDER BY
`favourite` DESC,

`active_date` ASC,
    `products`.`code` ASC,
    `products`.`name` ASC,
    `products`.`parent_id` ASC

 LIMIT 0, 20

AND  DATE(`commission`.`start_date`) <= DATE('2020-07-15')
      AND  ( DATE(`commission`.`end_date`) >= DATE('2020-07-15')
              OR  `commission`.`end_date` = '0000-00-00'

有几个问题： OR 很难优化。找到一些方法来避免它——比如删除这样的行，或者使用一个在遥远的将来而不是过去的结束日期。
不要在函数调用中隐藏列。
让我们看看 SHOW CREATE TABLE .
你不需要 DATE() 大概是“2020-07-15”。
另一方面，这是可以的： product_budget . start_date <=curdate（）

ORDER BY `favourite` DESC,
         `active_date` ASC,

除非您有mysql 8.0，否则没有索引可以处理 ORDER BY 混合了desc和asc(由于其他原因，可能无法使用索引。）

WHERE 0 OR (1  AND ...

动态构建查询，而不是像这样使用kludges。

LEFT JOIN ... ON ... foo = 1
``` `ON` 应该说明表之间的关系。 `foo = 1` 感觉更像是应该在 `WHERE` 子句（用于过滤）。在这两者之间移动 `ON` 以及 `WHERE` 可能会更改生成的行集。但我怀疑这是否应该 `JOIN` （代替 `LEFT JOIN` )或者测试应该在 `WHERE` ，或者它是否真的有效，你写的方式。
请提供 `EXPLAIN SELECT ...` 具有最大“行”的行可能是要关注的表。

GROUP BY products.id

很可能导致输出损坏。阅读“仅限完整分组”。
这会导致潜在的加速。
尽可能少的工作来获得 `id` 满足 `ORDER BY` 以及 `LIMIT` .
然后 `JOIN` 所有其他的table，包括 `products` ，以获取其他列。这可能会加快速度并消除上述错误。
实际变化在哪里 `LEFT JOIN` 进入子查询：

SELECT ...
vat_rate.rate AS vat_rate,
...
LEFT JOIN vat_rate ON products.vat_rate_id = vat_rate.id
...

-->

SELECT ...
( SELECT rate FROM vat_rate WHERE id = products.vat_rate_id
) AS vat_rate,
...
...

完成大部分工作，然后回来寻求更多建议。

mysql—我有一个相当大的sql查询，它被GROUPBY和ORDERBY语句减慢了速度优化的最佳方法是什么？

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