[ReneG]

Simply call onMySQLCheckAccount with a playerid parameter, and store the id in a global variable.

example

pawn Code:

new gSQLid[MAX_PLAYERS];

public MySQLCheckAccount(playerid) 
{
    new 
        query[128],
        name[MAX_PLAYER_NAME];
        
    GetPlayerName(playerid, name, sizeof(name));
    mysql_format(query, sizeof(query), "SELECT id FROM users WHERE `Name` = '%s' LIMIT 1", name);
    mysql_function_query(Handel, query, true,"onMySQLCheckAccount", "d", playerid);
    return 1;
}

public onMySQLCheckAccount(playerid) 
{
    new tmp[30];
    cache_field_content(0, "id", tmp); // The second parameter here is your field name 
    gSQLid[playerid] = strval(tmp); 
    return 1;
}