python - django 1.4 : I get an error in queryset extra -



python - django 1.4 : I get an error in queryset extra -

i have table table_object_price. fields: field_sale_currency_value name of currency, field_sale_whole_value name of price.

class object(node): id = models.onetoonefield('nod', parent_link=true, db_column='id') name = models.textfield(blank=true, null=true) field_sale_currency_value = models.textfield(blank=true, null=true) field_sale_whole_value = mintegerfield(blank=true, null=true)

this sql code makes sorting:

select *, case field_sale_currency_value when 'rur' field_sale_whole_value/40 when 'usd' field_sale_whole_value when 'eur' field_sale_whole_value/0.7423 field_sale_currency_value welhome.welhome_content_type_object order cost_usd ;

but need utilize django because function gets queryset:

def sort_queryset(queryset): queryset = queryset.extra(select={'cost_usd':'(case field_sale_currency_value when "rur" field_sale_whole_value/40 when "usd" field_sale_whole_value when "eur" field_sale_whole_value/0.7423 end)'}, order_by=["cost_usd"]) homecoming queryset

and not work.

error cannot resolve keyword 'cost_usd' field

from django docs:

if need order resulting queryset using of new fields or tables have included via extra() utilize order_by parameter extra() , pass in sequence of strings. these strings should either model fields (as in normal order_by() method on querysets), of form table_name.column_name or alias column specified in select parameter extra().

so, need as:

queryset = queryset.extra(select={'cost_usd':'(case field_sale_currency_value when "rur" field_sale_whole_value/40 when "usd" field_sale_whole_value when "eur" field_sale_whole_value/0.7423 end)'}) queryset = queryset.extra(order_by = ['cost_usd'])

python mysql django orm

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