User::find()->all(); //返回所有数据；
User::findOne($id); //返回 主键 id=1  的一条数据(举个例子)； 
User::find()->where(['name' => '小伙儿'])->one(); //返回 ['name' => '小伙儿'] 的一条数据；
User::find()->where(['name' => '小伙儿'])->all(); //返回 ['name' => '小伙儿'] 的所有数据；
User::find()->orderBy('id DESC')->all();   //是排序查询；
User::findBySql('SELECT * FROM user')->all(); //是用 sql  语句查询 user 表里面的所有数据；
User::findBySql('SELECT * FROM user')->one(); //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']); //是用 like 查询 name 等于 小伙儿的 数据
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()->batch(10); //每次取 10 条数据 
User::find()->each(10);  //每次取 10 条数据， 迭代查询

->andWhere['customer_id'=>$customerId]
->andWhere(['or'
    ['customer_name' => $customername],
    ['LIKE', 'phone' , $phone],
])
// WHERE customer_id=1 AND (customer_name='张三' OR phone LIKE 13123456789)

->andWhere['customer_id'=>$customerId]
->orWhere(['and'
    ['customer_name' => $customername],
    ['LIKE', 'phone' , $phone],
])
// WHERE customer_id=1 OR (customer_name='张三' AND phone LIKE 13123456789)

//2、如果需要些 and和or 的复合句，则：
->andWhere['customer_id'=>$customerId]
->andWhere(['or'
    ['status' => $status],
    ['and',
        ['customer_name' => $customername],
        ['LIKE', 'phone' , $phone],
    ],
])
// WHERE customer_id=1 AND ('status'=>1 OR (customer_name='张三' AND phone LIKE 13123456789))

//3、如果需要一些特殊的形式，则使用 new yiidbExpression();
->andWhere['customer_id'=>$customerId]
->andWhere(['or'
    ['status' => $status],
    ['and',
        ['customer_name' => $customername],
        ['IS NOT', phone' , new yiidbExpression('NULL')],
    ],
])
// WHERE customer_id=1 AND ('status'=>1 OR (customer_name='张三' AND phone IS NOT NULL))

User::updateAll(['status' => 1],['status' => 0,'flag' => 1]);

User::updateAll(['status' => 1],['and', ['status' => 0],['<>', 'flag', 1]]);