Question

我正在尝试编写一个查询来更新long a;表的外键invoice_id。

schedule

但我收到错误代码：1093。您无法在FROM子句中为更新指定目标表'schedule'。还有其他方法可以根据month和company_id更新CREATE TABLE `invoices` ( `id` int(11) NOT NULL AUTO_INCREMENT, `invoice_date` date NOT NULL, `company_id` int(11) NOT NULL, PRIMARY KEY (`id`)) CREATE TABLE `schedule` ( `id` int(11) NOT NULL AUTO_INCREMENT, `payment_date` date NOT NULL, `company_id` int(11) NOT NULL, `invoice_id` int(11) DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `id_UNIQUE` (`id`), KEY `fk_company_id_idx` (`company_id`), KEY `fk_schedule_invoices_idx` (`invoices_id`), CONSTRAINT `fk_schedule_company` FOREIGN KEY (`company_id`) REFERENCES `company` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION) CONSTRAINT `fk_schedule_invoices` FOREIGN KEY (`invoice_id`) REFERENCES `invoices` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION UPDATE schedule SET invoice_id=(SELECT id FROM invoices ORDER BY id DESC LIMIT 1) WHERE (company_id=1 AND (SELECT EXTRACT(MONTH FROM payment_date) as schedule_month FROM schedule WHERE company_id=1)= (SELECT EXTRACT(MONTH FROM invoice_date) as invoice_month FROM invoices WHERE company_id=1))吗？

修改实际上我想要实现的是创建一个触发器，在插入新发票后更新invoice_id表的invoice_id字段。该更新应基于company_id，年份和月份（同月的天数不同）。我只是尝试在不创建触发器的情况下进行更新

Here's a sample

Answer 1

正如我在帖子编辑中提到的，我需要设置schedule.invoice_id值。我是SQL的新手，所以我最初写错了一个条件。感谢@Michael Berkowski提示

UPDATE schedule s
JOIN invoices i
ON s.company_id=i.company_id
SET s.invoice_id=i.id
WHERE month(s.payment_date)=month(i.invoice_date)

错误代码：1093。您无法在FROM子句中为更新指定目标表'schedule'

1 个答案: