关于yii2中间表关联查询

业务需要用到这个中间表三表关联，自己写个demo实现 分享一下
test_tags表

CREATE TABLE `test_tags` (
`id`  int(10) NOT NULL ,
`name`  varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL ,
PRIMARY KEY (`id`)
)
ENGINE=InnoDB
DEFAULT CHARACTER SET=utf8 COLLATE=utf8_general_ci
ROW_FORMAT=DYNAMIC
;

INSERT INTO `test_tags` VALUES (1, 'php');
INSERT INTO `test_tags` VALUES (2, 'IT');
INSERT INTO `test_tags` VALUES (3, '编程');

test_article表

CREATE TABLE `test_article` (
`id`  int(10) NOT NULL AUTO_INCREMENT ,
`title`  varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL ,
PRIMARY KEY (`id`)
)
ENGINE=InnoDB
DEFAULT CHARACTER SET=utf8 COLLATE=utf8_general_ci
AUTO_INCREMENT=1
ROW_FORMAT=DYNAMIC
;

INSERT INTO `test_article` VALUES (1, '测试文章');

test_core表

CREATE TABLE `test_core` (
`id`  int(10) NOT NULL ,
`tags_id`  varchar(10) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL ,
`article_id`  int(10) NOT NULL ,
PRIMARY KEY (`id`)
)
ENGINE=InnoDB
DEFAULT CHARACTER SET=utf8 COLLATE=utf8_general_ci
ROW_FORMAT=DYNAMIC
;

INSERT INTO `test_core` VALUES (1, '1', 1);
INSERT INTO `test_core` VALUES (2, '2', 1);

在Article文章模型里设置关联

<?php

namespace frontend\models;

class Article extends \yii\db\ActiveRecord
{
    public static function tableName()
    {
        return 'test_article';
    }



    public function getTags(){
        return $this->hasMany(Tags::className(),['id'=>'tags_id'])
            ->viaTable('test_core',['article_id'=>'id'])
            ->asArray();
    }

}

跑一跑看看效果

    public function actionTest(){
        $model=Article::findOne(1);
        $data=$model->tags;
        var_dump($data);
    }

结果如下

 array(2) {
     [0]=>
     array(2) {
       ["id"]=>
       string(1) "1"
       ["name"]=>
       string(3) "php"
     }
     [1]=>
     array(2) {
       ["id"]=>
       string(1) "2"
       ["name"]=>
       string(2) "IT"
     }
}




 $data=Article::find()->joinWith('tags')->asArray()->all();
 var_dump($data);

结果：

array(2) {
  [0]=>
  array(3) {
    ["id"]=>
    string(1) "1"
    ["title"]=>
    string(6) "标题"
    ["tags"]=>
    array(2) {
      [0]=>
      array(2) {
        ["id"]=>
        string(1) "1"
        ["name"]=>
        string(3) "php"
      }
      [1]=>
      array(2) {
        ["id"]=>
        string(1) "2"
        ["name"]=>
        string(2) "IT"
      }
    }
  }
  [1]=>
  array(3) {
    ["id"]=>
    string(1) "2"
    ["title"]=>
    string(12) "测试文章"
    ["tags"]=>
    array(2) {
      [0]=>
      array(2) {
        ["id"]=>
        string(1) "2"
        ["name"]=>
        string(2) "IT"
      }
      [1]=>
      array(2) {
        ["id"]=>
        string(1) "3"
        ["name"]=>
        string(6) "编程"
      }
    }
  }
}