mysql-rijen tellen met lus

Waar u mee moet werken, is of de garantie nog geldig of verlopen is en de garantiedatum, dus u moet eerst een tabel maken die dat weergeeft:

select   product
       , IF( warranty >= NOW(), 1, 0 ) as valid
       , IF( warranty < NOW(), 1, 0 ) as expired
       , warranty as last
from     (
           select   product
                ,   ADDDATE( purchased, INTERVAL 5 YEAR ) as warranty
           from     productWarranty
         ) w
group by product
;

Dat zou je zoiets opleveren:

+---------+-------+---------+---------------------+
| product | valid | expired | warranty            |
+---------+-------+---------+---------------------+
| Hammer  |     1 |       0 | 2017-01-01 00:00:00 |
| Nipper  |     1 |       0 | 2017-01-01 00:00:00 |
| Nipper  |     1 |       0 | 2017-01-01 00:00:00 |
| Nipper  |     1 |       0 | 2017-01-01 00:00:00 |
| Saw     |     1 |       0 | 2017-01-01 00:00:00 |
| Saw     |     0 |       1 | 2011-01-01 00:00:00 |
| Saw     |     1 |       0 | 2017-01-01 00:00:00 |
| Saw     |     1 |       0 | 2017-01-01 00:00:00 |
+---------+-------+---------+---------------------+

Gebruik vervolgens verzamelfuncties om de informatie die u zoekt te filteren en samen te vatten:

select   product
       , SUM( IF( warranty >= NOW(), 1, 0 ) ) as valid
       , SUM( IF( warranty < NOW(), 1, 0 ) ) as expired
       , MAX( warranty ) as last
from     (
           select   product
                  , adddate( purchased, interval 5 year ) as warranty
           from productWarranty
         ) w
group by product
;

+---------+-------+---------+---------------------+
| product | valid | expired | last                |
+---------+-------+---------+---------------------+
| Hammer  |     1 |       0 | 2017-01-01 00:00:00 |
| Nipper  |     3 |       0 | 2017-01-01 00:00:00 |
| Saw     |     3 |       1 | 2017-01-01 00:00:00 |
+---------+-------+---------+---------------------+