How does thinkphp determine whether the username already exists in the database
$db_username = Db::name('用户表')->where('username','=','用户名')->find();
if($db_username != 0){
echo 'Username already exists';
}
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
$db_username = Db::name('用户表')->where('username','=','用户名')->find();
if($db_username != 0){
echo 'Username already exists';
}