Seth wrote: > > I'm trying to set up a relation from one table to another that will > give me a count of the unique user_id's that have posted a comment to > a post. > > For example: I've set up "post" as the parent table, and "comments" as > the child table (with post_id, user_id, comment_body, etc). What I > want to be able to do is once I do a "post = Session.query()", have > access to a "post.distinct_users" attribute which would essentially be > a "COUNT(DISTINCT(user_id))" on the comments table. > > I'm using DeclaritiveBase. If you a paste of my current setup I'd be > happy to oblige.
use a recipe almost identical to the second example in http://www.sqlalchemy.org/docs/05/mappers.html#sql-expressions-as-mapped-attributes . you just need to add a distinct() inside the count(). > > Thanks, > Seth > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
