diff --git a/swh/storage/db.py b/swh/storage/db.py
--- a/swh/storage/db.py
+++ b/swh/storage/db.py
@@ -78,7 +78,7 @@
         yield from execute_values_generator(
             cur, """
             select t.sha1, %s from (values %%s) as t (sha1)
-            left join content using (sha1)
+            inner join content using (sha1)
             """ % ', '.join(self.content_get_metadata_keys[1:]),
             ((sha1,) for sha1 in sha1s),
         )
diff --git a/swh/storage/in_memory.py b/swh/storage/in_memory.py
--- a/swh/storage/in_memory.py
+++ b/swh/storage/in_memory.py
@@ -354,7 +354,9 @@
             content: iterable of content identifiers (sha1)
 
         Returns:
-            an iterable with content metadata corresponding to the given ids
+            an iterable with content metadata corresponding to the given
+            ids
+
         """
         # FIXME: the return value should be a mapping from search key to found
         # content*s*
@@ -369,15 +371,7 @@
                 del d['ctime']
                 yield d
             else:
-                # FIXME: should really be None
-                yield {
-                    'sha1': sha1,
-                    'sha1_git': None,
-                    'sha256': None,
-                    'blake2s256': None,
-                    'length': None,
-                    'status': None,
-                }
+                continue
 
     def content_find(self, content):
         if not set(content).intersection(DEFAULT_ALGORITHMS):
diff --git a/swh/storage/storage.py b/swh/storage/storage.py
--- a/swh/storage/storage.py
+++ b/swh/storage/storage.py
@@ -545,7 +545,9 @@
             content: iterable of content identifiers (sha1)
 
         Returns:
-            an iterable with content metadata corresponding to the given ids
+            an iterable with content metadata corresponding to the given
+            ids
+
         """
         for metadata in db.content_get_metadata_from_sha1s(content, cur):
             yield dict(zip(db.content_get_metadata_keys, metadata))
diff --git a/swh/storage/tests/test_storage.py b/swh/storage/tests/test_storage.py
--- a/swh/storage/tests/test_storage.py
+++ b/swh/storage/tests/test_storage.py
@@ -464,13 +464,7 @@
 
         gen = swh_storage.content_get_metadata([missing_cont['sha1']])
 
-        # All the metadata keys are None
-        missing_cont.pop('data')
-        for key in missing_cont:
-            if key != 'sha1':
-                missing_cont[key] = None
-
-        assert list(gen) == [missing_cont]
+        assert list(gen) == []
 
     def test_content_get_random(self, swh_storage):
         swh_storage.content_add([data.cont, data.cont2, data.cont3])