想要每周获取总计价格
select @start:=adddate(Date_of_purchase,interval 2- dayofweek(Date_of_purchase)day),adddate(@start,interval 8- dayofweek(@start)day) as 'week end date',week(Date_of_purchase) as week,price from purchase where Date_of_purchase between '2017-12-16' and '2019-01-29';
+------------------------------------------------------------------------------+---------------+------+-------+
| @start:=adddate(Date_of_purchase,interval 2- dayofweek(Date_of_purchase)day) | week end date | week | price |
+------------------------------------------------------------------------------+---------------+------+-------+
| 2018-01-29 | 2018-02-04 | 4 | 300 |
| 2018-01-29 | 2018-02-04 | 4 | 70 |
| 2018-01-29 | 2018-02-04 | 4 | 70 |
| 2018-02-05 | 2018-02-11 | 5 | 180 |
| 2018-02-05 | 2018-02-11 | 5 | 180 |
| 2019-01-28 | 2019-02-03 | 4 | 190 |
| 2019-01-28 | 2019-02-03 | 4 | 390 |
| 2019-01-28 | 2019-02-03 | 4 | 390 |
| 2019-01-28 | 2019-02-03 | 4 | 180 |
| 2019-01-28 | 2019-02-03 | 4 | 70 |
| 2019-01-28 | 2019-02-03 | 4 | 70 |
| 2019-01-28 | 2019-02-03 | 4 | 70 |
| 2019-01-28 | 2019-02-03 | 4 | 20 |
| 2019-01-28 | 2019-02-03 | 4 | 45 |
| 2019-01-28 | 2019-02-03 | 4 | 70 |
| 2019-01-28 | 2019-02-03 | 4 | 70 |
| 2019-01-28 | 2019-02-03 | 4 | 70 |
| 2019-01-28 | 2019-02-03 | 4 | 300 |
| 2019-01-28 | 2019-02-03 | 4 | 200 |
+------------------------------------------------------------------------------+---------------+------+-------+
mysql> select sum(price), @start:=adddate(Date_of_purchase,interval 2- dayofweek(Date_of_purchase)day),adddate(@start,interval 8- dayofweek(@start)day) as 'week end date',week(Date_of_purchase) as week,price from purchase where Date_of_purchase between '2017-12-16' and '2019-01-29' group by @start;
+------------+------------------------------------------------------------------------------+---------------+------+-------+
| sum(price) | @start:=adddate(Date_of_purchase,interval 2- dayofweek(Date_of_purchase)day) | week end date | week | price |
+------------+------------------------------------------------------------------------------+---------------+------+-------+
| 320 | 2018-01-29 | 2018-02-04 | 4 | 70 |
| 370 | 2018-02-05 | 2018-02-11 | 5 | 180 |
| 2245 | 2018-01-29 | 2018-02-04 | 4 | 300 |
+------------+------------------------------------------------------------------------------+---------------+------+-------+
3 rows in set (1.94 sec)
第一行的总价格为440，显示为320