mysql query to generate a commision report based on referred members - mysql

Question

A person gets a 10% commision for purchases made by his referred friends.
There are two tables :
Reference table
Transaction table
Reference Table
Person_id Referrer_id
3 1
4 1
5 1
6 2
Transaction Table
Person_id Amount Action Date
3 100 Purchase 10-20-2011
4 200 Purchase 10-21-2011
6 400 Purchase 12-15-2011
3 200 Purchase 12-30-2011
1 50 Commision 01-01-2012
1 10 Cm_Bonus 01-01-2012
2 20 Commision 01-01-2012
How to get the following Resultset for Referrer_Person_id=1
Month Ref_Pur Earn_Comm Todate_Earn_Comm BonusRecvd Paid Due
10-2011 300 30 30 0 0 30
11-2011 0 0 30 0 0 30
12-2011 200 20 50 0 0 50
01-2012 0 0 50 10 50 0
Labels used above are:
Ref_Pur = Total Referred Friend's Purchase for that month
Earn_Comm = 10% Commision earned for that month
Todate_Earn_Comm = Total Running Commision earned upto that month
MYSQL CODE that i wrote
SELECT dx1.month,
dx1.ref_pur,
dx1.earn_comm,
( #cum_earn := #cum_earn + dx1.earn_comm ) as todate_earn_comm
FROM
(
select date_format(`date`,'%Y-%m') as month,
sum(amount) as ref_pur ,
(sum(amount)*0.1) as earn_comm
from transaction tr, reference rf
where tr.person_id=rf.person_id and
tr.action='Purchase' and
rf.referrer_id=1
group by date_format(`date`,'%Y-%m')
order by date_format(`date`,'%Y-%m')
)as dx1
JOIN (select #cum_earn:=0)e;
How to join the query to also include BonusRecvd,Paid and Due trnsactions, which is not dependent on reference table?
and also generate row for the month '11-2011', even though no trnx occured on that month

Answer 1

If you want to include commission payments and bonuses into the results, you'll probably need to include corresponding rows (Action IN ('Commision', 'Cm_Bonus')) into the initial dataset you are using to calculate the results on. Or, at least, that's what I would do, and it might be like this:
SELECT t.Amount, t.Action, t.Date
FROM Transaction t LEFT JOIN Reference r ON t.Person_id = r.Person_id
WHERE r.Referrer_id = 1 AND t.Action = 'Purchase'
OR t.Person_id = 1 AND t.Action IN ('Commision', 'Cm_Bonus')
And when calculating monthly SUMs, you can use CASE expressions to distinguish among Amounts related to differnt types of Action. This is how the corresponding part of the query might look like:
…
IFNULL(SUM(CASE Action WHEN 'Purchase' THEN Amount END) , 0) AS Ref_Pur,
IFNULL(SUM(CASE Action WHEN 'Purchase' THEN Amount END) * 0.1, 0) AS Earn_Comm,
IFNULL(SUM(CASE Action WHEN 'Cm_Bonus' THEN Amount END) , 0) AS BonusRecvd,
IFNULL(SUM(CASE Action WHEN 'Commision' THEN Amount END) , 0) AS Paid
…
When calculating the Due values, you can initialise another variable and use it quite similarly to #cum_earn, except you'll also need to subtract Paid, something like this:
(#cum_due := #cum_due + Earn_Comm - Paid) AS Due
One last problem seems to be missing months. To address it, I would do the following:
Get the first and the last date from the subset to be processed (as obtained by the query at the beginning of this post).
Get the corresponding month for each of the dates (i.e. another date which is merely the first of the same month).
Using a numbers table, generate a list of months covering the two calculated in the previous step.
Filter out the months that are present in the subset to be processed and use the remaining ones to add dummy transactions to the subset.
As you can see, the "subset to be processed" needs to be touched twice when performing these steps. So, for effeciency, I would insert that subset into a temporary table and use that table, instead of executing the same (sub)query several times.
A numbers table mentioned in Step #3 is a tool that I would recommend keep always handy. You would only need to initialise it once, and its uses for you may turn out numerous, if you pardon the pun. Here's but one way to populate a numbers table:
CREATE TABLE numbers (n int);
INSERT INTO numbers (n) SELECT 0;
INSERT INTO numbers (n) SELECT cnt + n FROM numbers, (SELECT COUNT(*) AS cnt FROM numbers) s;
INSERT INTO numbers (n) SELECT cnt + n FROM numbers, (SELECT COUNT(*) AS cnt FROM numbers) s;
INSERT INTO numbers (n) SELECT cnt + n FROM numbers, (SELECT COUNT(*) AS cnt FROM numbers) s;
INSERT INTO numbers (n) SELECT cnt + n FROM numbers, (SELECT COUNT(*) AS cnt FROM numbers) s;
INSERT INTO numbers (n) SELECT cnt + n FROM numbers, (SELECT COUNT(*) AS cnt FROM numbers) s;
INSERT INTO numbers (n) SELECT cnt + n FROM numbers, (SELECT COUNT(*) AS cnt FROM numbers) s;
INSERT INTO numbers (n) SELECT cnt + n FROM numbers, (SELECT COUNT(*) AS cnt FROM numbers) s;
INSERT INTO numbers (n) SELECT cnt + n FROM numbers, (SELECT COUNT(*) AS cnt FROM numbers) s;
/* repeat as necessary; every repeated line doubles the number of rows */
And that seems to be it. I will not post a complete solution here to spare you the chance to try to use the above suggestions in your own way, in case you are keen to. But if you are struggling or just want to verify that they can be applied to the required effect, you can try this SQL Fiddle page for a complete solution "in action".