Can't specify target table t4 for update in FROM clause - mysql

Question

I am trying to update my table:
UPDATE offers t1
SET t1.deleted_at = NOW()
WHERE t1.id
NOT IN
(
SELECT f.id
FROM (
SELECT ean, MIN(net_price) as minprice
FROM offers group BY ean
)
as x inner join offers as f on f.ean = x.ean and f.net_price = x.minprice
);
can anybody help me with this issue?
I realized that I needed to solve the issue through left join, but did not understand how to apply it in my case. Thank you.
Here is create table:
CREATE TABLE `offers` (
`id` bigint unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
`net_price` decimal(10,2) unsigned DEFAULT NULL,
`retail_price` decimal(10,2) unsigned DEFAULT NULL,
`supplier_id` bigint unsigned DEFAULT NULL,
`manufacturer_id` bigint unsigned DEFAULT NULL,
`stock` int DEFAULT NULL,
`ean` varchar(14) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
`mnn_id` bigint unsigned DEFAULT NULL,
`source_id` bigint unsigned NOT NULL,
`nds` smallint unsigned DEFAULT NULL,
`to_export` tinyint(1) DEFAULT NULL,
`created_at` timestamp NULL DEFAULT NULL,
`updated_at` timestamp NULL DEFAULT NULL,
`deleted_at` timestamp NULL DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `offers_supplier_id_foreign` (`supplier_id`),
KEY `offers_manufacturer_id_foreign` (`manufacturer_id`),
KEY `offers_mnn_id_foreign` (`mnn_id`),
KEY `offers_source_id_foreign` (`source_id`),
CONSTRAINT `offers_manufacturer_id_foreign` FOREIGN KEY (`manufacturer_id`) REFERENCES `manufacturers` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `offers_mnn_id_foreign` FOREIGN KEY (`mnn_id`) REFERENCES `mnns` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `offers_source_id_foreign` FOREIGN KEY (`source_id`) REFERENCES `sources` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `offers_supplier_id_foreign` FOREIGN KEY (`supplier_id`) REFERENCES `suppliers` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=25762 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

Answer 1

The error you are getting is
You can't specify target table 't1' for update in FROM clause
This is a problem specific to MySQL. You cannot directly access the updated table in a subquery, you need a sub subquery :-)
Replace
inner join offers as f
by
inner join (select * from offers) as f
hence to get the query working.
You don't need the join by the way. You can just write
UPDATE offers
SET deleted_at = NOW()
WHERE (ean, net_price) NOT IN
(
SELECT ean, MIN(net_price)
FROM (select * from offers) o
GROUP BY ean
);
Another way to write this (update all rows for which exists a lower price for the same EAN):
UPDATE offers t1
SET t1.deleted_at = NOW()
WHERE EXISTS
(
SELECT NULL
FROM (SELECT * FROM offers) t2
WHERE t2.ean = t1.ean
AND t2.net_price < t1.net_price
);
Demo: https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=bfa6d74a72d40fa445ea5fa9f95803d1
By the way: You may want to add the condition deleted_at IS NULL to your update statement in order not to update rows that are already logically deleted, if such rows exists.