Fixed #18247 -- Added cast to NUMERIC for Decimals on sqlite

On sqlite the SUM() of a decimal column doesn't have a NUMERIC type so
when comparing it to a string literal (which a Decimal gets converted to
in Django) it is not compared as expected.

1 files changed, 9 insertions, 0 deletions

diff --git a/django/db/models/expressions.py b/django/db/models/expressions.py
index 43061933e6..3ace285704 100644
--- a/django/db/models/expressions.py
+++ b/django/db/models/expressions.py
@@ -507,6 +507,15 @@ class Func(Expression):
         template = template or self.extra.get('template', self.template)
         return template % self.extra, params
 
+    def as_sqlite(self, *args, **kwargs):
+        sql, params = self.as_sql(*args, **kwargs)
+        try:
+            if self.output_field.get_internal_type() == 'DecimalField':
+                sql = 'CAST(%s AS NUMERIC)' % sql
+        except FieldError:
+            pass
+        return sql, params
+
     def copy(self):
         copy = super(Func, self).copy()
         copy.source_expressions = self.source_expressions[:]