var query = "select * from ? where info = 1;"
var params = [table];  //table = 'light'
connection.query(query, params, function(err, rows) { //this rows returns 'undefined'
        console.log(rows);
        var sql = "UPDATE ? SET info = ?,off_time = '?',run_time = '?' WHERE info = '1'";
        var run_time = time_cal(formatted, rows);
        var params = [table, data, formatted, run_time];
            connection.query(sql, params, function(err, rows) {
          if (err) {
            console.log(err);
          } else {
            console.log("update success!");
          }
        });
      });

mysql下表
柱式