ktv_customer')->where('customer_id', 1)->value('username');
```
#### 报错信息
```
PDOException: could notwebsite\ktv.com\webman\vendor\illuminate\database\Connection.php(376): Illuminate\Database\Connection->runsupport\App.php(131): Workerman\Worker::runAll()
#28 F:\website\ktv.com\webman\start.php(4): support\App::run