diff --git a/app/routes/forum/index.py b/app/routes/forum/index.py
index 023b881..d843872 100644
--- a/app/routes/forum/index.py
+++ b/app/routes/forum/index.py
@@ -83,12 +83,13 @@ def forum_page(f, page=1):
     # Count comments; this direct request avoids performing one request for
     # each topic.thread.comments.count() in the view, which the database
     # doesn't really appreciate performance-wise.
-    req_comment_counts = \
-        "SELECT thread_id, COUNT(*) FROM comment WHERE " + \
-        " OR ".join(f"thread_id={t.thread.id}" for t in topics.items) + \
-        " GROUP BY thread_id"
+    selection = " OR ".join(f"thread_id={t.thread.id}" for t in topics.items)
+    selection = "WHERE " + selection if selection else ""
 
-    comment_counts = db.session.execute(req_comment_counts)
+    comment_counts = db.session.execute(f"""
+        SELECT thread_id, COUNT(*) FROM comment {selection}
+        GROUP BY thread_id
+    """)
     comment_counts = dict(list(comment_counts))
 
     return render('/forum/forum.html', f=f, topics=topics, form=form,