I have an ORM setup with a "departments_milestones" table ("dm", 
DepartmentMilestone objects), with "department_id" and "seqOrder" Fields.  
Each department has a few records in this table, ordered within the 
department by "seqOrder" (so seqOrder is not unique).

Another object "ShotsStatus" contains a collection of these 
DepartmentMilestone objects, one for each department.  I'm interested in 
getting the ShotsStatus records that are at the "last" milestone in its 
department - the one with the highest "seqOrder" value for the department.  
In SQL I can do something like this, with a subquery to select the 
departmental milestone records, reverse sort them so the 'last' one is 
first, and LIMIT 1 to get it, which is compared to the outer record.

select * FROM shots_status ss
left outer join otherschema.departments_milestones dm on 
(dm.department_id=ss.dept_id AND dm.milestone_id = ss.status_id)
where ss.dept_id=723
and dm.id = (SELECT dmsq.id FROM plumber.departments_milestones dmsq WHERE 
dmsq.department_id=dm.department_id ORDER BY dmsq.seqOrder DESC LIMIT 1)

I'd like to create a hybrid property "isLast" on the DepartmentMilestone 
object that  returns True if it represents the 'last' milestone.  I'm 
having trouble figuring out what sort of sqlalchemy select coding I'd need 
to recreate the subquery from the SQL code to do this.

-- 
SQLAlchemy - 
The Python SQL Toolkit and Object Relational Mapper

http://www.sqlalchemy.org/

To post example code, please provide an MCVE: Minimal, Complete, and Verifiable 
Example.  See  http://stackoverflow.com/help/mcve for a full description.
--- 
You received this message because you are subscribed to the Google Groups 
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at https://groups.google.com/group/sqlalchemy.
For more options, visit https://groups.google.com/d/optout.

Reply via email to