PHP
$created = new DateTime('2024-01-27 09:41:00');
$visited = new DateTime('2024-01-29 09:41:00');
echo $visited->diff($created)->format('%a days'); // 2 days
SQL
SELECT created
, visited
, timestampdiff(DAY, created, visited) as days
FROM test_1;
+---------------------+---------------------+------+
| created | visited | days |
+---------------------+---------------------+------+
| 2024-01-27 09:41:00 | 2024-01-29 09:41:00 | 2 |
+---------------------+---------------------+------+