Yii框架下的where条件查询

条件查询

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

$cond就是我们所谓的条件，条件的写法也根据查询数据的不同存在差异，那么如何用yii2的方式来写查询条件呢？

[[简单条件]]

// 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']]  

//SQL:`type=1 AND (id=1 OR id=2)` //此写法'='可以换成其他操作符，例：in like != >=等  
$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]] or $cond = ['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]