diff --git a/sql.go b/sql.go
index 322214d..0f4f1ee 100644
--- a/sql.go
+++ b/sql.go
@@ -163,6 +163,7 @@ func initDB() {
 							,status			VARCHAR(32)
 							,end			DATETIME NOT NULL
 							,FOREIGN KEY (obj_id) REFERENCES obj(id) ON DELETE CASCADE
+							,KEY (lot_id)
 						  ) ENGINE = InnoDB CHARSET=utf8mb4 COLLATE utf8mb4_unicode_ci;`)
 	failOnError(err, "initDB : create table obj_msg_auction_announce")
 	log.Println("initDB : obj_msg_auction_announce created ...")