pow/round.js
function getMinWlByRoundIndex(conn, roundIndex, callback){
    conn.query(
		"SELECT min_wl FROM round where round_index=?", 
        [roundIndex],
		function(rows){
			if (rows.length !== 1)
                throw Error("Can not find the right round index");
            callback(rows[0].min_wl);
		}
	);
}
function getMinWlByRoundIndex(conn, roundIndex, callback){
    conn.query(
		"SELECT min_wl FROM round where round_index=?", 
        [roundIndex],
		function(rows){
			if (rows.length !== 1)
                throw Error("Can not find the right round index");
            callback(rows[0].min_wl);
		}
	);
}
function getMinWlByRoundIndex ( conn , roundIndex , callback ) { conn . query ( "SELECT min_wl FROM round where round_index=?" , [ roundIndex ] , function ( rows ) { if ( rows . length !== 1 ) throw Error ( "Can not find the right round index" ) ; callback ( rows [ 0 ] . min_wl ) ; } ) ; }
the MinWl maybe null
the MinWl maybe null