Question

I know enough MySQL to do simple joins but I’m lacking the knowledge when it comes to anything advanced. I know that I could strip out the rows in PHP but I believe that getting the query right is cleaner.

What I’m currently doing is:

Query:

SELECT DAYOFWEEK(r.`date`) AS weekNumber,  r.`date`AS scoreDate, qf.target, r.totalScore FROM results;

Result:

weekNumber, scoreDate, target, totalScore
4, '2012-02-29', 85, 100
3, '2012-03-06', 85, 100
3, '2012-03-06', 85, 75
3, '2012-03-06', 85, 42

Is it possible to:

• group by weekNumber,
• change the score date to show a ‘from and to date’ ,
• sum up the target ‘s and divide by the number of rows grouped together
• and the do the same for totalScore as we did with the target’s?

The outcome that I would like from the query is:

weekNumber, scoreDate, target, totalScore
4, '2012-02-29 to 2012-02-29', 85, 100
3, '2012-03-06 to 2012-03-06', 85, 72.3

Can someone help me create the query or tell me how I can produce the result that I’m looking for?

Thanks!

Answer 1

SELECT q1, AVG(q2) as target, max(q3) as `end`, MIN(q3) as `start` from q GROUP BY q1

the query above should do what you want. just change the q1 – q3 whit your fields. and q with you table name.

outcome:

________________________________________
| q1 | target | end        | start     |
----------------------------------------
| 3  | 8.0000 | 2012-03-09 | 2012-03-08|
----------------------------------------
| 4  | 2.0000 | 2012-03-07 | 2012-03-07|

Database:

________________________
| q1 | q2 | q 3        | 
------------------------
| 3  | 7  | 2012-03-09 |
| 3  | 9  | 2012-03-08 |
| 4  | 2  | 2012-03-07 |

source:
http://www.w3schools.com/sql/sql_func_avg.asp