Ticket #19360: 19360_v1.diff

django/db/backends/sqlite3/base.py

@@ -18 +18 @@
 from django.db.backends.sqlite3.client import DatabaseClient
 from django.db.backends.sqlite3.creation import DatabaseCreation
 from django.db.backends.sqlite3.introspection import DatabaseIntrospection
+from django.db.models import fields
+from django.db.models.sql import aggregates
 from django.utils.dateparse import parse_date, parse_datetime, parse_time
 from django.utils.functional import cached_property
 from django.utils.safestring import SafeBytes
@@ -127 +129 @@
         limit = 999 if len(fields) > 1 else 500
         return (limit // len(fields)) if len(fields) > 0 else len(objs)
 
+    def check_aggregate_support(self, aggregate):
+        # fix for ticket 19360
+        bad_fields = (fields.DateField, fields.DateTimeField, fields.TimeField)
+        bad_aggregates = (aggregates.Sum, aggregates.Avg,
+                          aggregates.Variance, aggregates.StdDev)
+        if isinstance(aggregate.source, bad_fields) and \
+           isinstance(aggregate, bad_aggregates):
+            raise NotImplementedError(
+                'You cannot use Sum, Avg, StdDev and Variance aggregations '
+                'on date/time fields in sqlite3 '
+                'since date/time is saved as text.')
+
     def date_extract_sql(self, lookup_type, field_name):
         # sqlite doesn't support extract, so we fake it with the user-defined
         # function django_extract that's registered in connect(). Note that

django/db/models/sql/query.py

@@ -119 +119 @@
         self.filter_is_sticky = False
         self.included_inherited_models = {}
 
-        # SQL-related attributes  
+        # SQL-related attributes
         # Select and related select clauses as SelectInfo instances.
         # The select is used for cases where we want to set up the select
         # clause to contain other than default fields (values(), annotate(),