date         hour   num_prodcuts
--------------------------------
2019-01-16   12:42           3.2
2019-01-17   13:40           4.2
2019-01-17   14:32             3

SELECT
    date,sum(num_products) asum
FROM
    Stadistics GROUP BY date;

date         asum
-----------------

2019-01-16    3.2
2019-01-17    7.2