django annotate

django-annotate.py

# django annoate 

#single field
SomeModel.objects.values('gender').annotate(Sum('hotdog_number'))
#mutiple fields
SomeModel.objects.values('gender','age').annotate(Sum('hotdog_number'))

"""odrder_by is needed
without order_by
[
{"name":"foo1","gender":"male","hotdog_number":2},
{"name":"foo2","gender":"fale","hotdog_number":2},
{"name":"foo3","gender":"fale","hotdog_number":2},
{"name":"foo4","gender":"male","hotdog_number":2},
{"name":"foo5","gender":"male","hotdog_number":2},
{"name":"foo6","gender":"fale","hotdog_number":2},
]
=>
[
{"gender":"male","hotdog_number":2},
{"gender":"fmale","hotdog_number":4},
{"gender":"male","hotdog_number":4},
{"gender":"male","hotdog_number":2},
]
"""

#single field
SomeModel.objects.values('gender').annotate(Sum('hotdog_number')).order_by('gender')
#mutiple fields
SomeModel.objects.values('gender','age').annotate(Sum('hotdog_number')).order_by('gender','age')
"""
with order_by
[
{"name":"foo1","gender":"male","hotdog_number":2},
{"name":"foo2","gender":"male","hotdog_number":2},
{"name":"foo3","gender":"male","hotdog_number":2},
{"name":"foo4","gender":"fmale","hotdog_number":1},
{"name":"foo5","gender":"fmale","hotdog_number":1},
{"name":"foo6","gender":"fmale","hotdog_number":1},
]
=>
[
{"gender":"male","hotdog_number":6},
{"gender":"fmale","hotdog_number":3},
]
"""