Execute SQL method stops working in MySQL

[IndieDev]

Hello.
Everything was working fine until recently. But now MySQL queries have stopped running.
Only simple sampling without conditions and only if I don’t use Execute SQL.
All other queries are terminated with “true” message and that’s it. No output data about the sample is given.
May be it is some kind of bug.
I have a selfhosted n8n instance. I updated to the latest version and the error is still there.
Please help the community and experts.

[MutedJam]

Hi @IndieDev, I am very sorry to hear you’re having trouble.

I’ve set up a dummy database including two tables with the below structure to reproduce this:

CREATE TABLE `authors` (
  `id` int NOT NULL AUTO_INCREMENT,
  `first_name` varchar(50) COLLATE utf8mb3_unicode_ci NOT NULL,
  `last_name` varchar(50) COLLATE utf8mb3_unicode_ci NOT NULL,
  `email` varchar(100) COLLATE utf8mb3_unicode_ci NOT NULL,
  `birthdate` date NOT NULL,
  `added` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB AUTO_INCREMENT=101 DEFAULT CHARSET=utf8mb3 COLLATE=utf8mb3_unicode_ci

CREATE TABLE `posts` (
  `id` int NOT NULL AUTO_INCREMENT,
  `author_id` int NOT NULL,
  `title` varchar(255) COLLATE utf8mb3_unicode_ci NOT NULL,
  `description` varchar(500) COLLATE utf8mb3_unicode_ci NOT NULL,
  `content` text COLLATE utf8mb3_unicode_ci NOT NULL,
  `date` date NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=101 DEFAULT CHARSET=utf8mb3 COLLATE=utf8mb3_unicode_ci

I’ve then added a bunch of dummy data and tried a number of different queries using n8n, but was seeing the expected result every time, even when including conditions or joins. For example using this workflow:

Result:

Perhaps you can provide an example database schema and workflow using which your problem can be reproduced?

[IndieDev]

Thank you very much for your help.
Now everything seems to be working as it should.
The sql code is now running with conditions and subqueries.