Re: Summing & Grouping in a Hierarchical Structure - Mailing list pgsql-sql
| From | Don Parris |
|---|---|
| Subject | Re: Summing & Grouping in a Hierarchical Structure |
| Date | |
| Msg-id | CAJ-7yokc9-KzAd3BRrVPwQywz-f7wkBd2N9Cno-eM9m5gjUAww@mail.gmail.com Whole thread Raw |
| In response to | Re: Summing & Grouping in a Hierarchical Structure (Misa Simic <misa.simic@gmail.com>) |
| Responses |
Re: Summing & Grouping in a Hierarchical Structure
|
| List | pgsql-sql |
Hi Misa,
I decided to try out ltree, and have made some progress with it. If I understand correctly how to use it, I simply insert the 'path' column into my table, using ltree as the data type. That eliminates the need for a category table, if I understand correctly. I just need to ensure the category path is correct for each line item in the transaction details table.However, I have difficulty figuring out how to sum the amounts as I would like:
test_ltree=> SELECT path, SUM(trans_amt) FROM testcat WHERE path ~ 'TOP.*{2}' GROUP BY path;
path | sum
------+-----
(0 rows)
This works fine:
test_ltree=> SELECT path, trans_amt FROM testcat;
path | trans_amt
-----------------------------------------+-----------
TOP.Transportation.Auto.Fuel | 50.00
TOP.Transportation.Auto.Maintenance | 30.00
TOP.Transportation.Auto.Fuel | 25.00
TOP.Transportation.Bicycle.Gear | 40.00
TOP.Transportation.Bicycle.Gear | 20.00
TOP.Transportation.Fares.Bus | 10.00
TOP.Transportation.Fares.Train | 5.00
TOP.Groceries.Food.Beverages | 30.00
TOP.Groceries.Food.Fruit_Veggies | 40.00
TOP.Groceries.Food.Meat_Fish | 80.00
TOP.Groceries.Food.Grains_Cereals | 30.00
TOP.Groceries.Beverages.Alcohol.Beer | 25.00
TOP.Groceries.Beverages.Alcohol.Spirits | 10.00
TOP.Groceries.Beverages.Alcohol.Wine | 50.00
TOP.Groceries.Beverages.Juice | 45.00
TOP.Groceries.Beverages.Other | 15.00
(16 rows)
test_ltree=> SELECT path, SUM(trans_amt) FROM testcat WHERE path ~ 'TOP.*{3}' GROUP BY path;
path | sum
-------------------------------------+-------
TOP.Groceries.Beverages.Juice | 45.00
TOP.Groceries.Beverages.Other | 15.00
TOP.Groceries.Food.Beverages | 30.00
TOP.Groceries.Food.Fruit_Veggies | 40.00
TOP.Groceries.Food.Grains_Cereals | 30.00
TOP.Groceries.Food.Meat_Fish | 80.00
TOP.Transportation.Auto.Fuel | 75.00
TOP.Transportation.Auto.Maintenance | 30.00
TOP.Transportation.Bicycle.Gear | 60.00
TOP.Transportation.Fares.Bus | 10.00
TOP.Transportation.Fares.Train | 5.00
(11 rows)
On Fri, Feb 22, 2013 at 4:00 AM, Misa Simic <misa.simic@gmail.com> wrote:
Hi,Have you considered maybe ltree datatype?I think it solves a lot of problems in topic....Kind regards,Misa
On Friday, February 15, 2013, Don Parris wrote:Hi all,I posted to this list some time ago about working with a hierarchical category structure. I had great difficulty with my problem and gave up for a time. I recently returned to it and resolved a big part of it. I have one step left to go, but at least I have solved this part.
Here is the original thread (or one of them):
http://www.postgresql.org/message-id/CAJ-7yonw4_qDCp-ZNYwEkR2jdLKeL8nfGc+-TLLSW=Rmo1VkbA@mail.gmail.comHere is my recent blog post about how I managed to show my expenses summed and grouped by a mid-level category:
http://dcparris.net/2013/02/13/hierarchical-categories-rdbms/
Specifically, I wanted to sum and group expenses according to categories, not just at the bottom tier, but at higher tiers, so as to show more summarized information. A CEO primarily wants to know the sum total for all the business units, yet have the ability to drill down to more detailed levels if something is unusually high or low. In my case, I could see the details, but not the summary. Well now I can summarize by what I refer to as the 2nd-level categories.Anyway, I hope this helps someone, as I have come to appreciate - and I mean really appreciate - the challenge of working with hierarchical structures in a 2-dimensional RDBMS. If anyone sees something I should explain better or in more depth, please let me know.Regards,Don--
D.C. Parris, FMP, Linux+, ESL Certificate
Minister, Security/FM Coordinator, Free Software AdvocateGPG Key ID: F5E179BE
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D.C. Parris, FMP, Linux+, ESL Certificate
Minister, Security/FM Coordinator, Free Software Advocate
GPG Key ID: F5E179BE