Yii2 数据库查询汇总

1. 基础查询:

User::find()->all();    //此方法返回所有数据;
 
User::findOne($id);   //此方法返回 主键 id=1  的一条数据(举个例子);
 
User::find()->where(['name' => '小伙儿'])->one();   //此方法返回 ['name' => '小伙儿'] 的一条数据;
 
User::find()->where(['name' => '小伙儿'])->all();   //此方法返回 ['name' => '小伙儿'] 的所有数据;
 
User::find()->orderBy('id DESC')->all();   //此方法是排序查询;
 
User::findBySql('SELECT * FROM user')->all();  //此方法是用 sql  语句查询 user 表里面的所有数据;
 
User::findBySql('SELECT * FROM user')->one();  //此方法是用 sql  语句查询 user 表里面的一条数据;
 
User::find()->andWhere(['sex' => '男', 'age' => '24'])->count('id');   //统计符合条件的总条数;
 
User::find()->andFilterWhere(['like', 'name', '小伙儿']); //此方法是用 like 查询 name 等于 小伙儿的 数据
 
User::find()->one();    //此方法返回一条数据;
 
User::find()->all();    //此方法返回所有数据;
 
User::find()->count();    //此方法返回记录的数量;
 
User::find()->average();    //此方法返回指定列的平均值;
 
User::find()->min();    //此方法返回指定列的最小值 ;
 
User::find()->max();    //此方法返回指定列的最大值 ;
 
User::find()->scalar();    //此方法返回值的第一行第一列的查询结果;
 
User::find()->column();    //此方法返回查询结果中的第一列的值;
 
User::find()->exists();    //此方法返回一个值指示是否包含查询结果的数据行;
 
User::find()->batch(10);  // 每次取 10 条数据
 
User::find()->each(10);  //每次取 10 条数据, 迭代查询

2. 直接查询

createCommand(执行原生的SQL语句) 
$sql= "SELECT u.account,i.* FROM sys_user as u left join user_info as i on u.id=i.user_id"; 
$rows=Yii::$app->db->createCommand($sql)->query(); 
查询返回多行:   
$command = Yii::$app->db->createCommand('SELECT * FROM post'); 
$posts = $command->queryAll();
  
返回单行
$command = Yii::$app->db->createCommand('SELECT * FROM post WHERE id=1'); 
$post = $command->queryOne();
   
查询多行单值: 
$command = Yii::$app->db->createCommand('SELECT title FROM post'); 
$titles = $command->queryColumn();
   
查询标量值/计算值: 
$command = Yii::$app->db->createCommand('SELECT COUNT(*) FROM post'); 
$postCount = $command->queryScalar();

3. 参数绑定

$post = Yii::$app->db->createCommand('SELECT * FROM post WHERE id=:id AND status=:status')
           ->bindValue(':id', $_GET['id'])
           ->bindValue(':status', 1)
           ->queryOne();
 
$params = [':id' => $_GET['id'], ':status' => 1];
 
$post = Yii::$app->db->createCommand('SELECT * FROM post WHERE id=:id AND status=:status')
           ->bindValues($params)
           ->queryOne();
            
$post = Yii::$app->db->createCommand('SELECT * FROM post WHERE id=:id AND status=:status', $params)

4. 执行非查询语句

// INSERT (table name, column values)
Yii::$app->db->createCommand()->insert('user', [
    'name' => 'Sam',
    'age' => 30,
])->execute();
 
// UPDATE (table name, column values, condition)
Yii::$app->db->createCommand()->update('user', ['status' => 1], 'age > 30')->execute();
 
// DELETE (table name, condition)
Yii::$app->db->createCommand()->delete('user', 'status = 0')->execute();
 
// table name, column names, column values
Yii::$app->db->createCommand()->batchInsert('user', ['name', 'age'], [
    ['Tom', 30],
    ['Jane', 20],
    ['Linda', 25],
])->execute();

5. 执行事务

$db = Yii::$app->db;
$transaction = $db->beginTransaction();
 
try {
    $db->createCommand($sql1)->execute();
    $db->createCommand($sql2)->execute();
    // ... executing other SQL statements ...
     
    $transaction->commit();
     
} catch(\Exception $e) {
 
    $transaction->rollBack();
     
    throw $e;
}

6. 关联查询

/**
 *客户表Model:CustomerModel
 *订单表Model:OrdersModel
 *国家表Model:CountrysModel
 *首先要建立表与表之间的关系
 *在CustomerModel中添加与订单的关系
 */    
Class CustomerModel extends \yii\db\ActiveRecord
{
    ...
    //客户和订单是一对多的关系所以用hasMany
    //此处OrdersModel在CustomerModel顶部别忘了加对应的命名空间
    //id对应的是OrdersModel的id字段,order_id对应CustomerModel的order_id字段
    public function getOrders()
    {
        return $this->hasMany(OrdersModel::className(), ['id'=>'order_id']);
    }
     
    //客户和国家是一对一的关系所以用hasOne
    public function getCountry()
    {
        return $this->hasOne(CountrysModel::className(), ['id'=>'Country_id']);
    }
    ....
}
       
// 查询客户与他们的订单和国家
CustomerModel::find()->with('orders', 'country')->all();
// 查询客户与他们的订单和订单的发货地址(注:orders 与 address都是关联关系)
CustomerModel::find()->with('orders.address')->all();
// 查询客户与他们的国家和状态为1的订单
CustomerModel::find()->with([
    'orders' => function ($query) {
        $query->andWhere('status = 1');
        },
        'country',
])->all();
posted @ 2021-04-23 17:28  MeetU  阅读(170)  评论(0编辑  收藏  举报