diff --git a/helper.php b/helper.php
index 51458c23..892fac8c 100644
--- a/helper.php
+++ b/helper.php
@@ -168,7 +168,7 @@ function validate($name = '', $layer = 'validate', $appendSuffix = false)
  * 实例化数据库类
  * @param string $name 操作的数据表名称（不含前缀）
  * @param array|string $config 数据库配置参数
- * @return \think\db\Connection
+ * @return \think\db\Query
  */
 function db($name = '', $config = [])
 {
diff --git a/library/think/db/Query.php b/library/think/db/Query.php
index 7610c9c7..fa191827 100644
--- a/library/think/db/Query.php
+++ b/library/think/db/Query.php
@@ -18,8 +18,8 @@ use think\Config;
 use think\Db;
 use think\db\Builder;
 use think\db\Connection;
-use think\db\DbException;
 use think\Exception;
+use think\exception\DbException;
 use think\exception\PDOException;
 use think\db\exception\BindParamException;
 use think\db\exception\ModelNotFoundException;