now() 和 dbExpression 在 yii2/mysql 中的奇怪行为

Question

我无法使以下代码的行为符合预期（删除过期记录）。简单的测试代码：

test_expire表定义：

CREATE TABLE `test_expire` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `expire` timestamp NOT NULL,
 PRIMARY KEY (`id`)
);

法典：

TestExpire::deleteAll();
$record = new TestExpire();
$record->expire = new Expression("NOW() + INTERVAL 1 MONTH");
$record->save();
$record = new TestExpire();
$record->expire = new Expression("NOW() + INTERVAL 1 YEAR");
$record->save();
$records = TestExpire::find('expire > :expire', ['expire' => date('Y-m-d')])->all();
echo "Records (" . count($records) . "):n";
foreach($records as $record) {
    echo "Expire: " . $record->expire . "n";
}
TestExpire::deleteAll("expire < NOW()");
$records = TestExpire::find('expire > :expire', ['expire' => date('Y-m-d')])->all();
echo "Records after delete 1: " . count($records) . "n";
TestExpire::deleteAll("expire < :expire", [':expire' => date('Y-m-d G:i:s')]);
$records = TestExpire::find('expire > :expire', ['expire' => date('Y-m-d')])->all();
echo "Records after delete 2: " . count($records) . "n";
TestExpire::deleteAll("expire < :expire", [':expire' => new Expression("NOW()")]);
$records = TestExpire::find('expire > :expire', ['expire' => date('Y-m-d')])->all();
echo "Records after delete 3: " . count($records) . "n";

好吧，我希望所有删除所有表达式都相同，每个表达式都不会删除记录。但最后一个确实如此。下面是输出：

Records (2):
Expire: 2015-01-05 14:52:02
Expire: 2015-12-05 14:52:02
Records after delete 1: 2
Records after delete 2: 2
Records after delete 3: 0

问题是为什么会发生这种情况以及如何使其按预期工作？

Answer 1

好吧，最后一个 sql 查询是：

DELETE FROM `test_expire` WHERE expire < 'NOW()';

而不是

DELETE FROM `test_expire` WHERE expire < NOW();

感谢您报告此错误，我在这里创建了一个问题：https://github.com/yiisoft/yii2/issues/6382

编辑：正如 Yii 问题跟踪器所解释的那样，参数绑定是一个 pdo 功能，不要将其与 db 表达式一起使用。