Forget my password

[j-ed]

You will find several request covering this point, if you use the search function of this forum (upper right corner):

https://help.nextcloud.com/search?q=change%20admin%20password

Here you find e.g. the recommendation to better change the recovery email address than playing around with the admin password:

Changing Admin password using PhpMySql

As i said, the password of an user can not be changed directly in mysql. But setting the e-mail address and then using the regular way could work. The userdata is stored in the table accounts.