mysql> select * from test;
+----+--------+
| id | name |
+----+--------+
| 1 | zhuai |
| 2 | heng | 
+----+--------+
18 rows in set (0.00 sec)

// 最基本的查询方式
$sql = "select * from test where 1";
$res = Test::findBySql($sql)->all();
var_dump(count($res)); // res->2 
// findbysql 防止sql注入方式
$id = '1 or 1=1';
$sql = "select * from test where id = " . $id;
$res = Test::findBySql($sql)->all();
var_dump(count($res)); // res-> 2
$sql = "select * from test where id = :id";
// 定位符会自动防止sql 注入
$res = Test::findBySql($sql,array(":id"=>$id))->all();
var_dump(count($res)); // res->1

<?php
namespace app\models;
use Yii;
use yii\db\ActiveRecord;
class Test extends ActiveRecord
{
// 可无，对应表：默认类名和表名匹配，则无需此函数
public static function tableName()
{
return 'test';
}
// 可无，验证器：主要用于校验各个字段
public function rules(){
return [
['id', 'integer'],
['name', 'string', 'length' => [0, 100]],
];
}
}

use app\models\Test;
增加操作
// add 操作
$test = new Test();
$test->name = 'test';
// 合法性校验
$test->validate();
if($test->hasErrors()){
echo "数据不合法";
die;
}
$test->save();

// select
// id = 1
$res = Test::find()->where(['id' => 1])->all();
var_dump(count($res)); //1
// id > 0
$res = Test::find()->where(['>','id',0])->all();
var_dump(count($res)); //2
// id > =1 id <=2
$res = Test::find()->where(['between','id',1,2])->all();
var_dump(count($res)); //2
// name字段like
$res = Test::find()->where(['like', 'name', 'cuihuan'])->all();
var_dump(count($res)); //2
// 查询的使用 obj->array
$res = Test::find()->where(['between','id',1,2])->asArray()->all();
var_dump($res[0]['id']); //2
// 批量查询,对于大内存操作的批量查询
foreach (Test::find()->batch(1) as $test) {
var_dump(count($test));
}

// delete 
// 选出来删除
$res = Test::find()->where(['id'=>1])->all();
$res[0]->delete();
// 直接删除
var_dump(Test::deleteAll('id>:id', array(':id' => 2)));

// 活动记录修改
$res = Test::find()->where(['id'=>4])->one();
$res->name = "update";
$res->save();

// 相应学生的所有score
$stu = Student::find()->where(['name'=>'xiaozhuai'])->one();
var_dump($stu->id);
// 基本获取
$scores_1 = $stu->hasMany('app\model\Score',['stu_id'=>$stu->id])->asArray()->all();
$scores_2 = $stu->hasMany(Score::className(),['stu_id'=>'id'])->asArray()->all();
var_dump($scores_1);
var_dump($scores_2);

<?php
namespace app\models;
use Yii;
use yii\db\ActiveRecord;
class Student extends ActiveRecord
{
public static function tableName()
{
return 'student';
}
// 获取分数信息
public function getScores()
{
$scores = $this->hasMany(Score::className(), ['stu_id' => 'id'])->asArray()->all();
return $scores;
}
}

// 函数封装之后调用
$scores = $stu->getScores();
var_dump($scores);
// 利用__get 的自动调用的方式
$scores = $stu->scores;
var_dump($scores);