1.简单查询：
%ignore_pre_1%应用实例：
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.关联查询：
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
应用实例：
//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) { $query->andWhere('status = 1'); }, 'country',])->all();
注：with中的orders对应getOrders
常见问题：在查询时加了->select();如下，要加上order_id，即关联的字段（比如：order_id）比如要在select中，否则会报错：undefined index order_id
// 查询客户与他们的订单和国家CustomerModel::find()->select('order_id')->with('orders', 'country')->all();findOne()和findAll():// 查询key值为10的客户$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()条件：
$customers = Customer::find()->where($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]]:将不同的条件组合在一起，用法举例：
//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 用法相同
//SQL:`id BETWEEN 1 AND 10`$cond = ['between', 'id', 1, 10]
[[in]]: not in 用法类似
//SQL:`id IN (1, 2, 3)`$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'`$cond = ['like', 'name', '%tester', false]
[[exists]]: not exists用法类似
//SQL:EXISTS (SELECT "id" FROM "users" WHERE "active"=1)$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]
常用查询：
// 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();
更新：
//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 = 2Customer::updateAll(['status' => 1], 'status = 2'); //update customer set status = 1 where status = 2 and uid = 1;Customer::updateAll(['status' => 1], ['status'=> '2','uid'=>'1']);
删除：
$model = Customer::findOne($id);$model->delete();$model->deleteAll(['id'=>1]);
批量插入：
Yii::$app->db->createCommand()->batchInsert(UserModel::tableName(), ['user_id','username'], [ ['1','test1'], ['2','test2'], ['3','test3'], ])->execute();
查看执行sql
//UserModel $query = UserModel::find()->where(['status'=>1]); echo $query->createCommand()->getRawSql();
推荐教程：YII教程
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