search

kapilratnani / django_hana

[Discontinued] Django db backend for SAP HANA
BSD 3-Clause "New" or "Revised" License
20 stars 13 forks source link

SELECT DISTINCT NOT WORKING #14

Closed alexgv closed 11 years ago

alexgv commented 11 years ago

Running a distinct query does not work if I run the following django it will produce the following sql

Django:

OrgBuilder.objects.order_by('Eff_Date').distinct('Eff_Date')

The sql will produce:

SELECT DISTINCT (OrgBuilder_orgbuilder.Eff_Date) OrgBuilder_orgbuilder.id, OrgBuilder_orgbuilder.Eff_Date, OrgBuilder_orgbuilder.instID, OrgBuilder_orgbuilder.Valid_From, OrgBuilder_orgbuilder.Valid_To, OrgBuilder_orgbuilder.Enable, OrgBuilder_orgbuilder.UserID_id FROM OrgBuilder_orgbuilder ORDER BY OrgBuilder_orgbuilder.Eff_Date ASC

that generates the following error:

Error: (257, 'sql syntax error: incorrect syntax near ".": line 1 col 50 (at pos 50)')

The sql it should produces should be like the following:

SELECT DISTINCT OrgBuilder_orgbuilder.Eff_Date FROM studentcloud_developer.OrgBuilder_orgbuilder ORDER BY OrgBuilder_orgbuilder.Eff_Date ASC

@kapilratnani

kapilratnani commented 11 years ago

Hey! i've been busy with office stuff. It would be great of you can give me a hand in fixing this bug. You can fork the project and send me a pull request.

Thanks.

kapilratnani commented 11 years ago

ok, i figured out the problem. Read here to get the full explanation here

In short, this type of query is only supported by PostgreSQL as of now. It uses a "SELECT DISTINCT ON" construct which HANA doesn't supports. Hence, you can only use distinct() not distinct(fields).

alexgv commented 11 years ago

Got ya. I guess when I send it the fields in the sql directly it really does not filter by eff date but by which one is distinct