diff --git a/wp-includes/query.php b/wp-includes/query.php
index 09c507b47e..756e5e5c52 100644
--- a/wp-includes/query.php
+++ b/wp-includes/query.php
@@ -1947,12 +1947,8 @@ class WP_Query {
 		if ( !empty( $this->tax_query ) ) {
 			$clauses = call_user_func_array( 'get_tax_sql', array( $this->tax_query, $wpdb->posts, 'ID', &$this) );
 
-			if ( empty($clauses['join']) && empty($clauses['where']) ) {
-				$where .= ' AND 0 = 1';	
-			} else {
-				$join .= $clauses['join'];
-				$where .= $clauses['where'];
-			}
+			$join .= $clauses['join'];
+			$where .= $clauses['where'];
 
 			if ( $this->is_tax ) {
 				if ( empty($post_type) ) {
diff --git a/wp-includes/taxonomy.php b/wp-includes/taxonomy.php
index 977e9bf16f..b2cb9543b2 100644
--- a/wp-includes/taxonomy.php
+++ b/wp-includes/taxonomy.php
@@ -552,9 +552,6 @@ function get_tax_sql( $tax_query, $primary_table, $primary_id_column ) {
 		if ( is_taxonomy_hierarchical( $taxonomy ) && $include_children ) {
 			_transform_terms( $terms, $taxonomies, $field, 'term_id' );
 
-			if ( empty( $terms ) )
-				continue;
-
 			$children = array();
 			foreach ( $terms as $term ) {
 				$children = array_merge( $children, get_term_children( $term, $taxonomy ) );
@@ -568,12 +565,12 @@ function get_tax_sql( $tax_query, $primary_table, $primary_id_column ) {
 			_transform_terms( $terms, $taxonomies, $field, 'term_taxonomy_id' );
 		}
 
-		if ( empty( $terms ) )
-			continue;
-
-		$terms = implode( ',', $terms );
-
 		if ( 'IN' == $operator ) {
+			if ( empty( $terms ) )
+				return array( 'join' => '', 'where' => ' AND 0 = 1');
+
+			$terms = implode( ',', $terms );
+
 			$alias = $i ? 'tt' . $i : $wpdb->term_relationships;
 
 			$join .= " INNER JOIN $wpdb->term_relationships";
@@ -585,6 +582,11 @@ function get_tax_sql( $tax_query, $primary_table, $primary_id_column ) {
 			$i++;
 		}
 		elseif ( 'NOT IN' == $operator ) {
+			if ( empty( $terms ) )
+				continue;
+
+			$terms = implode( ',', $terms );
+
 			$where .= " AND $primary_table.$primary_id_column NOT IN (
 				SELECT object_id 
 				FROM $wpdb->term_relationships 
@@ -599,6 +601,9 @@ function get_tax_sql( $tax_query, $primary_table, $primary_id_column ) {
 function _transform_terms( &$terms, $taxonomies, $field, $resulting_field ) {
 	global $wpdb;
 
+	if ( empty( $terms ) )
+		return;
+
 	if ( $field == $resulting_field )
 		return;