diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index cbc592a5c0..3555d71cc4 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -1046,7 +1046,7 @@ class WP_Tax_Query {
 			'join'  => array(),
 		);
 
-		$join = '';
+		$join = $where = '';
 
 		$this->clean_query( $clause );