I have Changed custom admin URL from admin panel,not working and getting admin url 404 error.
The pages you are talking about are specific to PHPMyAdmin, to help user have a more understandable interface, by only showing a specific number of rows. So it doesn't really matter which page they are, and it would change from a project to another.
What you need to do is look for the path you want with a SQL query (or with a search if you are using phpmyadmin or a similar tool).
You could use this request :
SELECT * FROM core_config_data WHERE path LIKE "%admin/url/%";
This will select all the rows where the path contains "admin/url/", then you should be able to modify them.
UPDATE `core_config_data` SET `value` = '0' WHERE `core_config_data`.`config_id` = 371;
You can also put value zero manually. Note down
config_id= 371; might be different,so please check same value and update.
Reload your store URL, if changes not reflect then clear your browser cache.
I hope It's helpful for you.