Search in inventory of other person


Hi Guys,

I set the vdk_inventory and vdk_recolt (inventory of players are saved in database) on my server and i would like to set a new feature for the cops :
I would like to set a command :
/search [PlayerID] for cops to see the inventory of a person on the server but I have a big problem :
In my database, the inventory are with ‘steamid’ so i would like to transform the PLAYERID in command in the steamid of the person to search his inventory in database.

Do you know how can I have the ‘steamid’ of a player with the ID of a player ? For example, if I write : /search 3 i would like to have a result : steamid:100010fdfvcd56

Can you help me ? Thanks a lot