yii2原生sql

先建立链接对象

$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(); 

要养成先查文档的习惯：
http://www.yiichina.com/doc/guide/2.0/db-dao