Refs #373 -- Added TupleIn subqueries.

1 files changed, 38 insertions, 3 deletions

diff --git a/django/db/models/fields/tuple_lookups.py b/django/db/models/fields/tuple_lookups.py
index a94582db95..6342937cd6 100644
--- a/django/db/models/fields/tuple_lookups.py
+++ b/django/db/models/fields/tuple_lookups.py
@@ -12,6 +12,7 @@ from django.db.models.lookups import (
     LessThan,
     LessThanOrEqual,
 )
+from django.db.models.sql import Query
 from django.db.models.sql.where import AND, OR, WhereNode
 
 
@@ -211,9 +212,14 @@ class TupleLessThanOrEqual(TupleLookupMixin, LessThanOrEqual):
 
 class TupleIn(TupleLookupMixin, In):
     def get_prep_lookup(self):
-        self.check_rhs_is_tuple_or_list()
-        self.check_rhs_is_collection_of_tuples_or_lists()
-        self.check_rhs_elements_length_equals_lhs_length()
+        if self.rhs_is_direct_value():
+            self.check_rhs_is_tuple_or_list()
+            self.check_rhs_is_collection_of_tuples_or_lists()
+            self.check_rhs_elements_length_equals_lhs_length()
+        else:
+            self.check_rhs_is_query()
+            self.check_rhs_select_length_equals_lhs_length()
+
         return self.rhs  # skip checks from mixin
 
     def check_rhs_is_collection_of_tuples_or_lists(self):
@@ -233,6 +239,25 @@ class TupleIn(TupleLookupMixin, In):
                 f"must have {len_lhs} elements each"
             )
 
+    def check_rhs_is_query(self):
+        if not isinstance(self.rhs, Query):
+            lhs_str = self.get_lhs_str()
+            rhs_cls = self.rhs.__class__.__name__
+            raise ValueError(
+                f"{self.lookup_name!r} subquery lookup of {lhs_str} "
+                f"must be a Query object (received {rhs_cls!r})"
+            )
+
+    def check_rhs_select_length_equals_lhs_length(self):
+        len_rhs = len(self.rhs.select)
+        len_lhs = len(self.lhs)
+        if len_rhs != len_lhs:
+            lhs_str = self.get_lhs_str()
+            raise ValueError(
+                f"{self.lookup_name!r} subquery lookup of {lhs_str} "
+                f"must have {len_lhs} fields (received {len_rhs})"
+            )
+
     def process_rhs(self, compiler, connection):
         rhs = self.rhs
         if not rhs:
@@ -255,10 +280,17 @@ class TupleIn(TupleLookupMixin, In):
 
         return Tuple(*result).as_sql(compiler, connection)
 
+    def as_sql(self, compiler, connection):
+        if not self.rhs_is_direct_value():
+            return self.as_subquery(compiler, connection)
+        return super().as_sql(compiler, connection)
+
     def as_sqlite(self, compiler, connection):
         rhs = self.rhs
         if not rhs:
             raise EmptyResultSet
+        if not self.rhs_is_direct_value():
+            return self.as_subquery(compiler, connection)
 
         # e.g.: (a, b, c) in [(x1, y1, z1), (x2, y2, z2)] as SQL:
         # WHERE (a = x1 AND b = y1 AND c = z1) OR (a = x2 AND b = y2 AND c = z2)
@@ -271,6 +303,9 @@ class TupleIn(TupleLookupMixin, In):
 
         return root.as_sql(compiler, connection)
 
+    def as_subquery(self, compiler, connection):
+        return compiler.compile(In(self.lhs, self.rhs))
+
 
 tuple_lookups = {
     "exact": TupleExact,