try using #semanage fcontext -a -t mysqld_db_t "/path(/.*)?" ...

After running that semanage command we should also run another command immediately to apply selinux context for that particular directory.

restorecon -Rv /directory_path

We can use another command to set selinux context, for this command don't run restorecon command because it will restore the context value to previous context

chcon -Rt /directory_path