Yii2中ActiveDataProvider无法获取关联Theme的name值问题

模型关联定义 #

Report 模型 #

public function getCampaign(): \yii\db\ActiveQuery
{
    return $this->hasOne(Campaign::class, ['cid' => 'cid']);
}

Campaign 模型 #

public function getStream()
{
    return $this->hasOne(Stream::class, ['id' => 'stream_id']);
}

Stream 模型 #

public function getTheme(): \yii\db\ActiveQuery
{
    return $this->hasOne(Theme::class, ['id' => 'theme_id']);
}

查询代码 #

$query = new Report();
$query = $query->find()->select($columns_array);
$query->joinWith('campaign.stream.theme t');
$query->groupBy('t.name');

问题现象 #

• 执行 dd($dataProvider->getModels()); 查看结果时，无法获取到Theme的name值
• 但通过 dd($query->prepare(\Yii::$app->db->queryBuilder)->createCommand()->rawSql); 查看生成的SQL语句，能正确查询到Theme的name值，生成的SQL如下：

SELECT "t"."name", 
sum(total_cost) AS "total_cost", 
sum(real_app_install) AS "real_app_install", 
sum(real_result_conversion) AS "real_result_conversion", 
sum(click) AS "click", 
sum(impression) AS "impression", 
sum(af_subs) AS "af_subs", 
sum(af_revenue) AS "af_revenue", 
avg(ctr) AS "ctr", 
avg(cpc) AS "cpc", 
avg(cpm) AS "cpm" 
FROM "reports" 
LEFT JOIN "campaigns" ON "reports"."cid" = "campaigns"."cid" 
LEFT JOIN "streams" ON "campaigns"."stream_id" = "streams"."id" 
LEFT JOIN "themes" "t" ON "streams"."theme_id" = "t"."id" 
GROUP BY "t"."name"

解决方案 #

问题根源是Yii2的ActiveRecord会自动把查询结果映射到Report模型的属性上，但t.name并没有对应到Report模型的字段，且分组查询的特性会导致嵌套关联模型无法自动填充。可以通过以下几种方式解决：

方法1：给Report模型添加虚拟属性 #

在Report模型中定义一个虚拟属性，查询时将t.name别名映射到该属性：

// Report.php 中添加属性
public $theme_name;

// 修改查询代码的select部分
$columns_array[] = 't.name AS theme_name';
$query = Report::find()->select($columns_array);
$query->joinWith('campaign.stream.theme t');
$query->groupBy('t.name');

之后就能通过 $model->theme_name 获取到Theme的name值。

方法2：将查询结果转为数组格式 #

设置ActiveDataProvider的asArray为true，让查询结果以数组形式返回，直接从数组中取name值：

$dataProvider = new ActiveDataProvider([
    'query' => $query,
    'asArray' => true,
]);

此时$dataProvider->getModels()返回数组，可通过$item['name']直接获取值。

方法3：预加载关联（分组场景不推荐） #

如果分组逻辑允许，可尝试用with()预加载关联，但分组后每个Report对应的关联数据可能不唯一，这种方法更适合普通列表查询，分组场景下容易出现数据不匹配的问题：

$query->with('campaign.stream.theme');

内容的提问来源于stack exchange，提问作者FeR-S