[RajatPawar]

pawn Код:

mysql_function_query("SELECT ID FROM Accounts")

is a threaded query. I am not sure if you can use store result, etc on that.

pawn Код:

CMD:...()
{
       mysql_function_query(connectionHandle, "SELECT COUNT(ID) FROM Accounts", true, "OnReturnNums", "d", playerid);
}

forward OnReturnNums(playerid);
public OnReturnNums(playerid)
{
     new rows, fields, Msg[40];
     cache_get_data(rows, fields, connectionHandle);
     
     format(Msg, sizeof(Msg), "Registered players: %i", rows);
     SendClientMessage(playerid, -1, Msg);
     return 1;
}

Use cache to get the data. Use COUNT() instead of SELECT * FROM to save memory and time.
I am assuming you know your connectionHandle and some code is assumed to be known.

Cheers