[Konstantinos]

Lack of information, the admin level is in the main players table or you have a separated table for admins? Either way, retrieving the player's name and use it in sscanf (1st parameter) with "r" or "u" specifier can easily figure out if the player is connected (if variable (3rd parameter) is not equal to INVALID_PLAYER_ID then player is connected).

Don't forget to set the admin level column as index in the table's structure to make it faster.