Author: russellm
Date: 2007-01-03 22:00:16 -0600 (Wed, 03 Jan 2007)
New Revision: 4283
Modified:
django/trunk/django/db/models/query.py
django/trunk/tests/modeltests/or_lookups/models.py
Log:
Fixed #2473 -- Added special case for '__in=[]' (empty set) queries, because
'WHERE attr IN ()' is invalid SQL on many backends. Thanks, Gary Wilson.
Modified: django/trunk/django/db/models/query.py
===================================================================
--- django/trunk/django/db/models/query.py 2007-01-03 22:40:06 UTC (rev
4282)
+++ django/trunk/django/db/models/query.py 2007-01-04 04:00:16 UTC (rev
4283)
@@ -641,7 +641,15 @@
except KeyError:
pass
if lookup_type == 'in':
- return '%s%s IN (%s)' % (table_prefix, field_name, ','.join(['%s' for
v in value]))
+ in_string = ','.join(['%s' for id in value])
+ if in_string:
+ return '%s%s IN (%s)' % (table_prefix, field_name, in_string)
+ else:
+ # Most backends do not accept an empty string inside the IN
+ # expression, i.e. cannot do "WHERE ... IN ()". Since there are
+ # also some backends that do not accept "WHERE false", we instead
+ # use an expression that always evaluates to False.
+ return '0=1'
elif lookup_type == 'range':
return '%s%s BETWEEN %%s AND %%s' % (table_prefix, field_name)
elif lookup_type in ('year', 'month', 'day'):
Modified: django/trunk/tests/modeltests/or_lookups/models.py
===================================================================
--- django/trunk/tests/modeltests/or_lookups/models.py 2007-01-03 22:40:06 UTC
(rev 4282)
+++ django/trunk/tests/modeltests/or_lookups/models.py 2007-01-04 04:00:16 UTC
(rev 4283)
@@ -69,6 +69,21 @@
>>> Article.objects.filter(Q(pk=1) | Q(pk=2) | Q(pk=3))
[<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
+# You could also use "in" to accomplish the same as above.
+>>> Article.objects.filter(pk__in=[1,2,3])
+[<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
+
+>>> Article.objects.filter(pk__in=[1,2,3,4])
+[<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
+
+# Passing "in" an empty list returns no results ...
+>>> Article.objects.filter(pk__in=[])
+[]
+
+# ... but can return results if we OR it with another query.
+>>> Article.objects.filter(Q(pk__in=[]) | Q(headline__icontains='goodbye'))
+[<Article: Goodbye>, <Article: Hello and goodbye>]
+
# Q arg objects are ANDed
>>> Article.objects.filter(Q(headline__startswith='Hello'),
Q(headline__contains='bye'))
[<Article: Hello and goodbye>]
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