Why does Django Queryset say: TypeError: Complex aggregates require an alias? -


i have django class follows:

class mymodel(models.model):     my_int = models.integerfield(null=true, blank=true,)     created_ts = models.datetimefield(default=datetime.utcnow, editable=false)

when run following queryset, error:

>>> django.db.models import max, f, func >>> mymodel.objects.all().aggregate(max(func(f('created_ts'), function='unix_timestamp'))) traceback (most recent call last):   file "<console>", line 1, in <module>   file "myvirtualenv/lib/python2.7/site-packages/django/db/models/query.py", line 297, in aggregate     raise typeerror("complex aggregates require alias") typeerror: complex aggregates require alias

how adjust queryset don't error? want find instance of mymodel latest created_ts. , want use unix_timestamp function it.

i'm not running same django version, think this'll work:

mymodel.objects.all().aggregate(latest=max(func(f('created_ts'), function='unix_timestamp')))

note latest keyword argument in there. that's key (i think, again can't test this).


-

Comments

Post a Comment

Popular posts from this blog

c# - Binding a comma separated list to a List<int> in asp.net web api -

the default binder in web api expecst http://url.com/webapi/report/?pageids=3243&pageids=2365 to bind public ihttpactionresult report(list<int> pageids){ // exciting webapi code} i wish bind http://url.com/webapi/report/?pageids=3243,2365 as running out of space in url get . i have created class public class commaseparatedmodelbinder : system.web.http.modelbinding.imodelbinder { public bool bindmodel(httpactioncontext actioncontext, modelbindingcontext bindingcontext) { //binding in here } } and registered in webapiconfig.cs var provider = new simplemodelbinderprovider( typeof(list<int>), new commaseparatedmodelbinder()); config.services.insert(typeof(modelbinderprovider), 0, provider); i have altered method signature use model binder so public ihttpactionresult report( [modelbinder] list<int> pageids){ // exciting webapi code} however break point in binder not being ...
Read more

how to prompt save As Box in Excel Interlop c# MVC 4 -

i want export excel sheet using excel interloop... i have datatable convert excel sheet... now there way save file using save dialogue box in mvc 4 here code public string datatabletoexcel(datatable dt, string htmlheading, string key) { try { microsoft.office.interop.excel.application excel; microsoft.office.interop.excel.workbook excelworkbook; microsoft.office.interop.excel.worksheet excelsheet; microsoft.office.interop.excel.range excelcellrange; excel = new microsoft.office.interop.excel.application(); excel.visible = false; excel.displayalerts = false; excelworkbook = excel.workbooks.add(type.missing); excelsheet = (microsoft.office.interop.excel.worksheet)excelworkbook.activesheet; excelsheet.name = "sheet1"; dataset ...
Read more

xslt 1.0 - How to access or retrieve mets content of an item from another item? -

my use case have item has link in item. example, item 123456789/152 has metadata field dc.relation.hasversion=123456789/717 . within item view of 123456789/152 , how can retrieve values of metadata of 123456789/717 ? example, want retrieve dc.language.iso value of 123456789/717 123456789/152 . i looked @ related items feature in dspace don't know how metadata displayed in related items list pulled items in list. i using dspace version 5.3 mirage 2 theme . edit based on schweerelos answer, below actual code. using custom metadata field dc.relation.languageversion . basically, want link other version instead of displaying value, display dc.language.iso of other version in item-view.xsl . i've incorporated answer of schweerelos question in code just displaying value of dc.relation.languageversion . sample values of dc.relation.languageversion 10665.1/9843 ; 10665.1/9844 ie not complete uri handle. thanks in advance! actual code <xsl:template name=...
Read more