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]

    //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]