如何使用属性mutator合并两个输入字段？

It's clear how to set and get attributes when it's about one field. But how can I merge two input fields using attribute mutator?

For example I have publish_date and publish_time, which I insert in the DB together and want to set attribute publish_date to become publish_date + publish_time.

You can grab other attributes from the attributes array on the model.

public function setPublishDateAttribute($value) 
{
    $this->attributes['publish_date'] = $value + $this->attributes['publish_time'];
}