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Changes between Initial Version and Version 1 of Ticket #24431

-              initial
+              v1
 Another Example with some toy models:
+{{{#!python
 class Address(models.Model):
     city = models.CharField(max_length=40)
 …
     data = models.CharField(max_length=40)
     author = models.ForeignKey(Author)
+}}}
 For each author, select a count of their total blog entries, as well as a custom boolean value based on their address:
+{{{#!python
 Author.objects.all().annotate(blogpost_count=Count('blogpost')).select_related('address').extra(select={'in_maryland':"address.state='MD'"}).count()
+}}}
 This is fine until you append the count()
 …
 A potential fix is in django/db/models/sql/query.py line 396 in get_aggregation().
 Change
+{{{#!python
 inner_query.select_related = False
+}}}
 To
+{{{#!python
 if not self._extra: #Skip optimization, extra() fields might need these joins
     inner_query.select_related = False
+}}}
 The cause appears to be a performance optimization (don't do joins if the results don't appear the affect the aggregate).