diff --git a/wp-includes/comment-functions.php b/wp-includes/comment-functions.php
index 300df69695..fb94031e30 100644
--- a/wp-includes/comment-functions.php
+++ b/wp-includes/comment-functions.php
@@ -657,7 +657,7 @@ function check_comment($author, $email, $url, $comment, $user_ip, $user_agent, $
 			else
 				return false;
 		} elseif( $author != '' && $email != '' ) {
-			$ok_to_comment = $wpdb->get_var("SELECT comment_approved FROM $wpdb->comments WHERE comment_author = '$author' AND comment_author_email = '$email' and comment_approved = '1' ");
+			$ok_to_comment = $wpdb->get_var("SELECT comment_approved FROM $wpdb->comments WHERE comment_author = '$author' AND comment_author_email = '$email' and comment_approved = '1' LIMIT 1");
 			if ( 1 == $ok_to_comment && false === strpos( $email, get_settings('moderation_keys')) )
 				return true;
 			else