diff --git a/lib/galaxy/managers/users.py b/lib/galaxy/managers/users.py
index 8d08d767f355..d9912dfd6651 100644
--- a/lib/galaxy/managers/users.py
+++ b/lib/galaxy/managers/users.py
@@ -414,19 +414,20 @@ def tags_used(self, user, tag_models=None):
         # get all the taggable model TagAssociations
         if not tag_models:
             tag_models = [v.tag_assoc_class for v in self.app.tag_handler.item_tag_assoc_info.values()]
-        # create a union of subqueries for each for this user - getting only the tname and user_value
-        all_tags_query = None
-        for tag_model in tag_models:
-            subq = self.session().query(tag_model.user_tname, tag_model.user_value).filter(tag_model.user == user)
-            all_tags_query = subq if all_tags_query is None else all_tags_query.union(subq)
 
-        # if nothing init'd the query, bail
-        if all_tags_query is None:
+        if not tag_models:
             return []
 
+        # create a union of select statements for each tag model for this user - getting only the tname and user_value
+        all_tags_stmt = None
+        for tag_model in tag_models:
+            stmt = select(tag_model.user_tname, tag_model.user_value).where(tag_model.user == user)
+            all_tags_stmt = stmt if all_tags_stmt is None else all_tags_stmt.union(stmt)
+
         # boil the tag tuples down into a sorted list of DISTINCT name:val strings
-        tags = all_tags_query.distinct().all()
-        tags = [(f"{name}:{val}" if val else name) for name, val in tags]
+        all_tags_stmt = all_tags_stmt.distinct()
+        tag_tuples = self.session().exectute(all_tags_stmt)
+        tags = [(f"{name}:{val}" if val else name) for name, val in tag_tuples]
         # consider named tags while sorting
         return sorted(tags, key=lambda str: re.sub("^name:", "#", str))