diff -u b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
--- b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
+++ b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
@@ -248,7 +248,7 @@
    * {@inheritdoc}
    */
   public function count() {
-    return $this->prepareQuery()->countQuery()->execute()->fetchField();
+    return $this->query()->countQuery()->execute()->fetchField();
   }
 
   /**