yii2原生sql

先创建连接对象

$connection = new \yii\db\Connection([

    'dsn' => $dsn,

     'username' => $username,

     'password' => $password,

]);

$connection->open();

查询返回多行：

$command = $connection->createCommand('SELECT * FROM post');

$posts = $command->queryAll();

返回单行：

$command = $connection->createCommand('SELECT * FROM post WHERE id=1');

$post = $command->queryOne();

查询多行单值：

$command = $connection->createCommand('SELECT title FROM post');

$titles = $command->queryColumn();

查询标量值/计算值：

$command = $connection->createCommand('SELECT COUNT(*) FROM post');

$postCount = $command->queryScalar();

巴特西