参考：https://github.com/yii2-chinesization/yii2-zh-cn/blob/master/guide-zh-cn/db-dao.md
返回多行：
$command = $connection->createCommand('SELECT * FROM post');$posts = $command->queryAll();翻译单行：$command = $connection->createCommand('SELECT * FROM post WHERE id=1');$post = $command->queryOne();查询多列：$command = $connection->createCommand('SELECT title FROM post');$titles = $command->queryColumn();查询标量/计算值：$command = $connection->createCommand('SELECT COUNT(*) FROM post');$postCount = $command->queryScalar();更新数据：$command = $connection->createCommand('UPDATE post SET status=1 WHERE id=1');$command->execute();一次插入单行/多行：// INSERT $connection->createCommand()->insert('user', [ 'name' => 'Sam', 'age' => 30, ])->execute();// INSERT 一次插入多行 $connection->createCommand()->batchInsert('user', ['name', 'age'], [ ['Tom', 30], ['Jane', 20], ['Linda', 25], ])->execute();更新：
$connection->createCommand()->update('user', ['status' => 1], 'age > 30')->execute();
删除：$connection->createCommand()->delete('user', 'status = 0')->execute();预处理：$command = $connection->createCommand('SELECT * FROM post WHERE id=:id');$command->bindValue(':id', $_GET['id']);$post = $command->query();一次预处理语句执行多次：$command = $connection->createCommand('DELETE FROM post WHERE id=:id');$command->bindParam(':id', $id); $id = 1;$command->execute(); $id = 2;$command->execute();
建表：$connection->createCommand()->createTable('post', [ 'id' => 'pk', 'title' => 'string', 'text' => 'text',]);
