sysbench测试生成的表sbtest1，主键为id列，以下查询返回了两行数据，怎么回事，难道随机数返回多，成了in表达式？

mysql> select id,k,c,pad from sbtest1 where id=round(1+rand()*10000000);
+---------+---------+-------------------------------------------------------------------------------------------------------------------------+-------------------------------------------------------------+
| id      | k       | c                                                                                                                       | pad                                                         |
+---------+---------+-------------------------------------------------------------------------------------------------------------------------+-------------------------------------------------------------+
| 2898778 | 5028649 | 46962879307-12528096878-98533271975-28588894546-89347604371-19950165403-76306205107-40316135032-44372394143-89198007136 | 99652023711-77989728125-60857111039-43729275867-39065311690 |
| 5880059 | 4325123 | 64531747760-63415903997-13051684140-84404429789-21701326784-38596788914-13518889645-16369987468-69025001759-63770817627 | 49533924409-06736919496-87250632017-19533775297-00877260384 |
+---------+---------+-------------------------------------------------------------------------------------------------------------------------+-------------------------------------------------------------+
2 rows in set (9.12 sec)

mysql> show create table sbtest1\G;
*************************** 1. row ***************************
       Table: sbtest1
Create Table: CREATE TABLE `sbtest1` (
  `id` int NOT NULL AUTO_INCREMENT,
  `k` int NOT NULL DEFAULT '0',
  `c` char(120) NOT NULL DEFAULT '',
  `pad` char(60) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`),
  KEY `k_1` (`k`)
) ENGINE=InnoDB AUTO_INCREMENT=10000007 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
1 row in set (0.00 sec)

ERROR: 
No query specified