diff --git a/sql.go b/sql.go
index 1c43ddb..90abe42 100644
--- a/sql.go
+++ b/sql.go
@@ -154,6 +154,7 @@ 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")
 
@@ -161,6 +162,7 @@ func initDB() {
 							 obj_id			BIGINT UNSIGNED NOT NULL
 							,lot_id         BIGINT UNSIGNED 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_upd_req")