Yii2框架数据库增删改查

查询操作：

User::find()->one();    //返回一条数据；
User::find()->all();    //返回所有数据；
User::find()->count();    //返回记录的数量；
User::find()->average();   //返回指定列的平均值；
User::find()->min();    //返回指定列的最小值 ；
User::find()->max();   //返回指定列的最大值 ；
User::find()->scalar();    //返回值的第一行第一列的查询结果；
User::find()->column();    //返回查询结果中的第一列的值；
User::find()->exists();    //返回一个值指示是否包含查询结果的数据行；

User::find()->where(['name' => 'username'])->one();   此方法返回 ['name' => 'username'] 的一条数据；
User::find()->where(['name' => 'username'])->all();   此方法返回 ['name' => 'username'] 的所有数据；
User::find()->andWhere(['sex' => '男', 'age' => '24'])->count('id');   统计符合条件的总条数；
$student = Student::find()->where(['status'=>ConfigHelper::STATUS_ABLE])->count();
$student = Student::findOne(7688);
$student =(new Query())->from('student')->select(['id','username'])->where(['id'=>7688])->one();

$connection = Yii::$app->db;
$sql = "select * from student limit 1";
$student = $connection->createCommand($sql)->queryAll();

$sql = 'SELECT * FROM student limit 10';
 $student = Student::findBySql($sql)->asArray()->all();

each查询

 $query = (new Query())->from('student')->where(['classes_id'=>6])->batch(10);

echo '<pre>';
foreach ($query as $students){
    var_dump($students);
}

batch查询

$query = (new Query())->from('student')->where(['classes_id'=>6])->each(10);
echo '<pre>';
foreach ($query as $students){
    var_dump($students);
}

新增操作：

$model = newUser();
$model->username = 'username';
$model->age      = '20';
$model->insert();

$connection = Yii::$app->db;
$r = $connection->createCommand()
->insert('classes',['name'=>'class','school_id'=>67843,'comment'=>'test','is_pay'=>0,'account_type_id'=>2])
->execute();

$class = new Classes();
$class->name = 'class2';
$class->school_id = 67843;
$r = $class->save();

批量插入

$connection = Yii::$app->db;
$r = $connection->createCommand()
->batchInsert('classes',['name','school_id'],[['class3','67843'],['class4','67843']])
->execute();

修改操作：

$User = User::findOne($id);
$User->name = 'zhangsan';
$User->save(); // 等同于 $User->update();

删除操作：

User::deleteAll('name = username');    删除 name = username 的数据；
User::findOne($id)->delete(); 删除主键为 $id变量 值的数据库；
User::deleteAll('age > :age AND sex = :sex', [':age' => '20', ':sex' => '1']);  删除符合条件的数据；