Databases
StackOverflow2013
Postsdbo
POCumulative monthly reporting
Body
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POCumulative monthly reporting
    text
    copied!<p>I have a MySQL table of photovoltaic electricity generation data (pvdata) from which I need to produce a monthly summary table. A simplified table is shown:</p> <p>id &nbsp; &nbsp; &nbsp; &nbsp; date &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; time &nbsp; &nbsp; &nbsp; pvdata<br> 1 &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; 2012-01-01 &nbsp; &nbsp; 10:00 &nbsp; &nbsp; 50<br> 1 &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; 2012-01-31 &nbsp; &nbsp; 12:00 &nbsp; &nbsp; 60<br> 1 &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; 2012-02-10 &nbsp; &nbsp; 13:00 &nbsp; &nbsp;&nbsp;70<br> 2 &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; 2012-02-08 &nbsp; &nbsp; 10:00 &nbsp; &nbsp; 12<br> 2 &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; 2012-03-20 &nbsp; &nbsp; 10:00 &nbsp; &nbsp; 17<br></p> <p>The monthly summary table needs to show the cumulative generation for all systems in the database, regardless of whether I have received data for that month, so for example month 3 below contains the total generation from id = 1 (data received in month 2). </p> <p>Also there may be more than one data point for an id in the same month, so the report must report the max(data) for the month.</p> <p>year &nbsp; &nbsp; &nbsp; month &nbsp; &nbsp; cum_data<br> 2012 &nbsp; &nbsp;&nbsp; 1 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 60<br> 2012 &nbsp; &nbsp;&nbsp; 2 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 82<br> 2012 &nbsp; &nbsp;&nbsp; 3 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 87<br></p> <p>I am pretty new to this, so have struggled for a while. The best I can come up with shows the cumulative total for the month, but without including the cumulative total for ids for which there is no data in the current month:</p> <pre><code>CREATE TEMPORARY TABLE intermed_gen_report SELECT year(date) AS year, month(date) AS month, id, max(pvdata) AS maxpvdata FROM pvdata GROUP BY id, year(date), month(date) ORDER BY year(date), month(date); SELECT year, month, SUM(maxpvdata) AS cum_data FROM intermed_gen_report GROUP BY year, month ORDER BY year, month; </code></pre> <p>Giving: </p> <p>year &nbsp; &nbsp; &nbsp; month &nbsp; &nbsp; cum_data<br> 2012 &nbsp; &nbsp;&nbsp; 1 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 60<br> 2012 &nbsp; &nbsp;&nbsp; 2 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 82<br> 2012 &nbsp; &nbsp;&nbsp; 3 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 17<br></p>
 

Querying!

 
Guidance
An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload