[1.11.x] Fixed #28781 -- Added QuerySet.values()/values_list() support for union(), difference(), and intersection().

Thanks Tim Graham for the review.
Backport of 2d3cc94284674638c334670903d49565039d77ae from master

1 files changed, 5 insertions, 0 deletions

diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py
index 6ec2284a91..9888816c8d 100644
--- a/django/db/models/sql/compiler.py
+++ b/django/db/models/sql/compiler.py
@@ -390,6 +390,11 @@ class SQLCompiler(object):
         parts = ()
         for compiler in compilers:
             try:
+                # If the columns list is limited, then all combined queries
+                # must have the same columns list. Set the selects defined on
+                # the query on all combined queries, if not already set.
+                if not compiler.query.values_select and self.query.values_select:
+                    compiler.query.set_values(self.query.values_select)
                 parts += (compiler.as_sql(),)
             except EmptyResultSet:
                 # Omit the empty queryset with UNION and with DIFFERENCE if the