Question

I am able to retrieve the sum/total sales for all items in a particular week using the code below.

select week(real_pur_date) as week, itemcode, sum(quantity)
from sales
where week(real_pur_date) = week(20120620)
group by itemcode;

The output is:

+------+----------+---------------+
| week | itemcode | sum(quantity) |
+------+----------+---------------+
|   25 | KB001    |            11 |
|   25 | KB002    |             2 |
|   25 | KB003    |             3 |
+------+----------+---------------+

which is what I wanted

The question is how can I query MySql to return the range of dates in week 25 back into the result table?
For example,
1. range of dates in week 24 is 10-06-2012 to 16-06-2012.
2. range of dates in week 25 is 17-06-2012 to 23-06-2012.

Thanks in advance.

Answer 1

I’m not a MySQL guy so I had to try to convert from SQL Server functions. But, the basic math is there. I’ll let you determine how you want to pass or calculate @YEARSTART and @YEAREND.

DECLARE @YEARSTART datetime, @YEAREND datatime
SET @YEARSTART='1/1/2012'
SET @YEAREND = '12/31/2012'

SELECT A.week, CASE WHEN (@YEARSTART + INTERVAL (8-DAYOFWEEK(@STARTYEAR)+(week-2)*7) DAY) < @YEARSTART 
                 THEN @YEARSTART
                 ELSE (@YEARSTART + INTERVAL (8-DAYOFWEEK(@STARTYEAR)+(week-2)*7) DAY) 
               END AS WeekStart,
               CASE WHEN (@YEARSTART + INTERVAL (7-DAYOFWEEK(@STARTYEAR)+(week-1)*7) DAY) > @YEAREND
                 THEN @YEAREND
                 ELSE (@YEARSTART + INTERVAL (7-DAYOFWEEK(@STARTYEAR)+(week-1)*7) DAY)
               END AS WeekEnd,
      A.itemcode, A.SumQty 
FROM
(
select week(real_pur_date) as week, itemcode, sum(quantity) AS SumQty
from sales
where week(real_pur_date) = week(20120620)
group by itemcode
) AS A