I have query like this :

SELECT EXTRACT(MONTH FROM d.mydate) AS synmonth, SUM(apcp) AS apcptot
FROM t_synop_data2 d
WHERE d.mydate
BETWEEN '2011-01-01' AND '2011-12-31' 
AND d.idx_synop = '06712'
GROUP BY synmonth

This query adds all rain (apcp) in a month like this :

1   32.8  => from 2011.01.01 to 2011.01.31
2   27.2 => from 2011.02.01 to 2011.02.28
3   21.0
4   21.8
5   88.5
6   131.4
7   118.6
8   57.1
9   80.9
10  84.6
11  1.1
12  143.5 => from 2011.12.01 to 2011.12.31

That's what I want, but with a little difference.

This difference is that i have to adds apcp from day 2 in the month to day 1 next month and then return a result like above.

1   132.8 => from 2011.01.02 to 2011.02.01
2   27.2  => from 2011.02.02 to 2011.03.01
3   21.0
4   21.8
5   88.5
6   131.4
7   118.6
8   57.1
9   80.9
10  84.6
11  1.1
12  143.5 => from 2011.12.02 to 2012.01.01

I tried something with add_date(), extract() or date_format() but without result.

Thank you for your answer Vince

• mysql
• date
• group-by

Here is the query :

SELECT EXTRACT(MONTH FROM ADDDATE(d.mydate,-1) ) AS synmonth
, SUM(apcp) AS apcptot
FROM t_synop_data2 AS d
WHERE ADDDATE(d.mydate,-1) BETWEEN '2011-01-01' AND '2012-12-31'
AND d.idx_synop = '06712'
GROUP BY synmonth

You can check the result by adding two columns like this:

SELECT EXTRACT(MONTH FROM ADDDATE(d.mydate,-1) ) AS synmonth
, SUM(apcp) AS apcptot
, MIN(d.mydate) AS date_min
, MAX(d.mydate) AS date_max
FROM t_synop_data2 AS d
WHERE ADDDATE(d.mydate,-1) BETWEEN '2011-01-01' AND '2012-12-31'
AND d.idx_synop = '06712'
GROUP BY synmonth

You can group by EXTRACT(MONTH FROM d.mydate - INTERVAL 1 DAY)

SELECT EXTRACT(MONTH FROM d.mydate) AS synmonth, SUM(apcp) AS apcptot
FROM t_synop_data2 d
WHERE d.mydate
BETWEEN '2011-01-01' AND '2011-12-31' 
AND d.idx_synop = '06712'
GROUP BY EXTRACT(MONTH FROM d.mydate - INTERVAL 1 DAY)