Detailed explanation of addition, deletion, modification and query of Yii2.0 database operations

1. Simple query:

one(): 根据查询结果返回查询的第一条记录。
all(): 根据查询结果返回所有记录。
count(): 返回记录的数量。
sum(): 返回指定列的总数。
average(): 返回指定列的平均值。
min(): 返回指定列的最小值。
max(): 返回指定列的最大值。
scalar(): 返回查询结果的第一行中的第一列的值。
column(): 返回查询结果中的第一列的值。
exists(): 返回一个值，该值指示查询结果是否有数据。
where(): 添加查询条件
with(): 该查询应执行的关系列表。
indexBy(): 根据索引的列的名称查询结果。
asArray(): 以数组的形式返回每条记录。

Application example:

Customer::find()->one();    此方法返回一条数据；
Customer::find()->all();    此方法返回所有数据；
Customer::find()->count();    此方法返回记录的数量；
Customer::find()->average();    此方法返回指定列的平均值；
Customer::find()->min();    此方法返回指定列的最小值 ；
Customer::find()->max();    此方法返回指定列的最大值 ；
Customer::find()->scalar();    此方法返回值的第一行第一列的查询结果；
Customer::find()->column();    此方法返回查询结果中的第一列的值；
Customer::find()->exists();    此方法返回一个值指示是否包含查询结果的数据行；
Customer::find()->asArray()->one();    以数组形式返回一条数据；
Customer::find()->asArray()->all();    以数组形式返回所有数据；
Customer::find()->where($condition)->asArray()->one();    根据条件以数组形式返回一条数据；
Customer::find()->where($condition)->asArray()->all();    根据条件以数组形式返回所有数据；
Customer::find()->where($condition)->asArray()->orderBy('id DESC')->all();    根据条件以数组形式返回所有数据,并根据ID倒序；

2. Related query:

ActiveRecord::hasOne()：返回对应关系的单条记录
ActiveRecord::hasMany()：返回对应关系的多条记录

Application example:

//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 yiidbActiveRecord
{
    ...
    
    public function getOrders()
    {
        //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
        return $this->hasMany(OrdersModel::className(), ['id'=>'order_id']);
    }
     
    public function getCountry()
    {
        //客户和国家是一对一的关系所以用hasOne
        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
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();

Note: orders in with correspond to getOrders

Frequently Asked Questions:

Added - during query >select();As follows, order_id must be added, that is, the associated field (for example: order_id) must be in the select, otherwise an error will be reported: undefined index order_id

// 查询客户与他们的订单和国家
CustomerModel::find()->select('order_id')->with('orders', 'country')->all();
findOne()和findAll():

// 查询key值为10的客户
$customer = Customer::findOne(10);
$customer = Customer::find()->where(['id' => 10])->one();
// 查询年龄为30，状态值为1的客户
$customer = Customer::findOne(['age' => 30, 'status' => 1]);
$customer = Customer::find()->where(['age' => 30, 'status' => 1])->one();
// 查询key值为10的所有客户
$customers = Customer::findAll(10);
$customers = Customer::find()->where(['id' => 10])->all();
// 查询key值为10，11,12的客户
$customers = Customer::findAll([10, 11, 12]);
$customers = Customer::find()->where(['id' => [10, 11, 12]])->all();
// 查询年龄为30，状态值为1的所有客户
$customers = Customer::findAll(['age' => 30, 'status' => 1]);
$customers = Customer::find()->where(['age' => 30, 'status' => 1])->all();

where( )Condition:

$customers = Customer::find()->where($cond)->all(); 

$cond写法举例：

// SQL: (type = 1) AND (status = 2).
$cond = ['type' => 1, 'status' => 2] 

// SQL:(id IN (1, 2, 3)) AND (status = 2)
$cond = ['id' => [1, 2, 3], 'status' => 2] 

//SQL:status IS NULL
$cond = ['status' => null]

[[and]]: Combine different conditions together, usage example:

//SQL:`id=1 AND id=2`
$cond = ['and', 'id=1', 'id=2']

//SQL:`type=1 AND (id=1 OR id=2)`
$cond = ['and', 'type=1', ['or', 'id=1', 'id=2']]

[[or] ]:

//SQL:`(type IN (7, 8, 9) OR (id IN (1, 2, 3)))`
$cond = ['or', ['type' => [7, 8, 9]], ['id' => [1, 2, 3]]

[[not]]:

//SQL:`NOT (attribute IS NULL)`
$cond = ['not', ['attribute' => null]]

[[between]]: not between Same usage

//SQL:`id BETWEEN 1 AND 10`
$cond = ['between', 'id', 1, 10]

[[in]]: not in Usage is similar

//SQL:`id IN (1, 2, 3)`
$cond = ['in', 'id', [1, 2, 3]]

//IN条件也适用于多字段
$cond = ['in', ['id', 'name'], [['id' => 1, 'name' => 'foo'], ['id' => 2, 'name' => 'bar']]]

//也适用于内嵌sql语句
$cond = ['in', 'user_id', (new Query())->select('id')->from('users')->where(['active' => 1])]

[[like]]:

//SQL:`name LIKE '%tester%'`
$cond = ['like', 'name', 'tester']

//SQL:`name LIKE '%test%' AND name LIKE '%sample%'`
$cond = ['like', 'name', ['test', 'sample']]

//SQL:`name LIKE '%tester'`
$cond = ['like', 'name', '%tester', false]

[ [exists]]: not exists usage is similar to

//SQL:EXISTS (SELECT "id" FROM "users" WHERE "active"=1)
$cond = ['exists', (new Query())->select('id')->from('users')->where(['active' => 1])]
此外，您可以指定任意运算符如下

//SQL:`id >= 10`
$cond = ['>=', 'id', 10]

//SQL:`id != 10`
$cond = ['!=', 'id', 10]

Common queries:

// WHERE admin_id >= 10 LIMIT 0,10
 User::find()->select('*')->where(['>=', 'admin_id', 10])->offset(0)->limit(10)->all()
// SELECT `id`, (SELECT COUNT(*) FROM `user`) AS `count` FROM `post`   
 $subQuery = (new Query())->select('COUNT(*)')->from('user');    
 $query = (new Query())->select(['id', 'count' => $subQuery])->from('post');
  // SELECT DISTINCT `user_id` ... 
 User::find()->select('user_id')->distinct();

Update:

//update();
//runValidation boolen 是否通过validate()校验字段 默认为true 
//attributeNames array 需要更新的字段 
$model->update($runValidation , $attributeNames);  

//updateAll();
//update customer set status = 1 where status = 2
Customer::updateAll(['status' => 1], 'status = 2'); 

//update customer set status = 1 where status = 2 and uid = 1;
Customer::updateAll(['status' => 1], ['status'=> '2','uid'=>'1']);

Delete:

$model = Customer::findOne($id);
$model->delete();
$model->deleteAll(['id'=>1]);

Batch insert:

Yii::$app->db->createCommand()->batchInsert(UserModel::tableName(), ['user_id','username'], [
    ['1','test1'],
    ['2','test2'],
    ['3','test3'],   
])->execute();

View execution sql

//UserModel 
$query = UserModel::find()->where(['status'=>1]); 
echo $query->createCommand()->getRawSql();

Recommended tutorial: YII Tutorial

The above is the detailed content of Detailed explanation of addition, deletion, modification and query of Yii2.0 database operations. For more information, please follow other related articles on the PHP Chinese website!