#24485: Support for annotate(end=F('start') + F('duration'), output_field=DateTimeField) -------------------------------------+------------------------------------- Reporter: yoyoma | Owner: nobody Type: New feature | Status: new Component: Database layer | Version: master (models, ORM) | Severity: Normal | Resolution: Keywords: durationfield, | Triage Stage: aggregation, annotation | Unreviewed Has patch: 0 | Needs documentation: 0 Needs tests: 0 | Patch needs improvement: 0 Easy pickings: 0 | UI/UX: 0 -------------------------------------+-------------------------------------
Comment (by jarshwah): What would you expect the SQL output of SUM(date_field) to be? Most databases (all?) do not allow Sum(date). The argument to Sum has to be numeric or convertable to numeric. Sum(interval) works for some backends. What I suspect you really want though is this: {{{ Ticket.objects.annotate( expires_at=(F('active_at') + F('duration'), output_field=models.DateTimeField()) ) }}} Note that I've removed the Sum. We're now just adding two fields. I'm not 100% sure that this is supported on all backends, but if it's not it should be. Also note that I've wrapped both F() expressions in brackets so that I can apply the output_field to the combination of both. Can you give that a go and report back please? -- Ticket URL: <https://code.djangoproject.com/ticket/24485#comment:2> Django <https://code.djangoproject.com/> The Web framework for perfectionists with deadlines. -- You received this message because you are subscribed to the Google Groups "Django updates" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-updates+unsubscr...@googlegroups.com. To post to this group, send email to django-updates@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/django-updates/064.dcd93912153eea979bb9041736b8e2c1%40djangoproject.com. For more options, visit https://groups.google.com/d/optout.