diff --git a/includes/database/query.inc b/includes/database/query.inc
index ac14c4a2e5e77cc610d61130239ae812a6e7adf1..f1aed5e52aed0f7eee465bd5cc960db5739c04fe 100644
--- a/includes/database/query.inc
+++ b/includes/database/query.inc
@@ -31,10 +31,8 @@ interface QueryConditionInterface {
    *   dependent on the $operator.
    * @param $operator
    *   The comparison operator, such as =, <, or >=. It also accepts more complex
-   *   options such as IN, LIKE, or BETWEEN.
-   * @param $num_args
-   *   For internal use only. This argument is used to track the recursive calls when
-   *   processing complex conditions.
+   *   options such as IN, LIKE, or BETWEEN. Defaults to IN if $value is an array
+   *   = otherwise.
    * @return
    *   The called object.
    */
@@ -794,11 +792,8 @@ public function __construct(DatabaseConnection $connection, $table, array $optio
     $this->condition = new DatabaseCondition('AND');
   }
 
-  public function condition($field, $value = NULL, $operator = '=') {
-    if (!isset($num_args)) {
-      $num_args = func_num_args();
-    }
-    $this->condition->condition($field, $value, $operator, $num_args);
+  public function condition($field, $value = NULL, $operator = NULL) {
+    $this->condition->condition($field, $value, $operator);
     return $this;
   }
 
@@ -939,11 +934,8 @@ public function __construct(DatabaseConnection $connection, $table, array $optio
     $this->condition = new DatabaseCondition('AND');
   }
 
-  public function condition($field, $value = NULL, $operator = '=') {
-    if (!isset($num_args)) {
-      $num_args = func_num_args();
-    }
-    $this->condition->condition($field, $value, $operator, $num_args);
+  public function condition($field, $value = NULL, $operator = NULL) {
+    $this->condition->condition($field, $value, $operator);
     return $this;
   }
 
@@ -1094,7 +1086,10 @@ public function count() {
     return count($this->conditions) - 1;
   }
 
-  public function condition($field, $value = NULL, $operator = '=') {
+  public function condition($field, $value = NULL, $operator = NULL) {
+    if (!isset($operator)) {
+      $operator = is_array($value) ? 'IN' : '=';
+    }
     $this->conditions[] = array(
       'field' => $field,
       'value' => $value,
diff --git a/includes/database/select.inc b/includes/database/select.inc
index 65b31bc6cacdea4be5b318d429730753424ce8ad..449ab11f4527b113f41fa08bea51fd8f6c19c845 100644
--- a/includes/database/select.inc
+++ b/includes/database/select.inc
@@ -423,7 +423,7 @@ public function getMetaData($key) {
 
   /* Implementations of QueryConditionInterface for the WHERE clause. */
 
-  public function condition($field, $value = NULL, $operator = '=') {
+  public function condition($field, $value = NULL, $operator = NULL) {
     $this->query->condition($field, $value, $operator);
     return $this;
   }