Describe the bug

When simulating a UPDATE query, the matched rows count is wrong sometimes. This happens if the column contains NULL values.

The generated query for count is SELECT `b` FROM `test` WHERE `a` = '2' AND (`b` <> 'test') but it probably should be SELECT `b` FROM `test` WHERE `a` = '2' AND (`b` <> 'test' OR `b` IS NULL)

To Reproduce

Steps to reproduce the behavior:

1. Create table

CREATE TABLE `test` (
  `id` int(10) UNSIGNED NOT NULL,
  `a` varchar(255) DEFAULT NULL,
  `b` text DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;

INSERT INTO `test` (`id`, `a`, `b`) VALUES
(1, '1', 'test'),
(2, '1', NULL),
(3, '1', NULL),
(4, '1', NULL),
(5, '1', 'test'),
(6, '2', NULL),
(7, '2', NULL),
(8, '2', 'test'),
(9, '2', NULL),
(10, '2', 'test');

ALTER TABLE `test`
  ADD PRIMARY KEY (`id`);

ALTER TABLE `test`
  MODIFY `id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=11;
COMMIT;

2. Go to SQL tab and simulate this query
   UPDATE `test` SET `b` = 'test' WHERE `a` = '2'
3. See the count 0 which is wrong. It should be 3.

Expected behavior

The count should be accurate.

Screenshots

Server configuration

• phpMyAdmin version: 5.2.2-dev, 6.0.0-dev