i want to install mysql 5.7 in ubuntu 22.04, but during the installation process, i got error:
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B7B3B788A8D3785C
Reading package lists... Done
W: GPG error: http://repo.mysql.com/apt/ubuntu bionic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B7B3B788A8D3785C
E: The repository 'http://repo.mysql.com/apt/ubuntu bionic InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
solution:
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys B7B3B788A8D3785C