['in', ['id', 'name'], [['id' => 1, 'name' => 'foo'], ['id' => 2, 'name' => 'bar']] ] 怎么理解
where方法的解释（http://www.yiichina.com/doc/api/2.0/yii-db-query#where()-detail）里有个in的例子不太懂， 可以解释下吗？
To create a composite IN condition you can use and array for the column name and value, where the values are indexed by the column name: ['in', ['id', 'name'], [['id' => 1, 'name' => 'foo'], ['id' => 2, 'name' => 'bar']] ].
