diff --git a/db.py b/db.py
index 55235c3..46c0397 100644
--- a/db.py
+++ b/db.py
@@ -54,9 +54,14 @@ class DBConn:
         if self.db_type == "postgres":
             import psycopg2.extras
             cur = self._conn.cursor(cursor_factory=psycopg2.extras.RealDictCursor)
-            cur.execute(sql, params)
+            if params is None:
+                cur.execute(sql)
+            else:
+                cur.execute(sql, params)
             return cur
         else:
+            if params is None:
+                return self._conn.execute(sql)
             return self._conn.execute(sql, params)
 
     def executemany(self, sql: str, seq):