如何在 Yii $criteria 中使用 DATE_ADD？

模型.php

// Declare $datetime_limit
public datetime_limit;

控制器.php

// datetime_limit should be the actual datetime + 5 days
$criteria->select="DATE_ADD(NOW(), INTERVAL 5 DAY) AS datetime_limit";

错误信息：

Active record "Users" is trying to select an invalid column "DATE_ADD(NOW()". Note, the column must exist in the table or be an expression with alias.

Edit 1:

我想使用关系表（多对多）过滤带有条件的查找。 所以datetime_limit不能有关系events.datetime。 我怎样才能做到这一点？

$criteria->select=array("DATE_ADD(NOW(), INTERVAL 5 DAY) AS datetime_limit");
$criteria->with=array('events');
$criteria->having='datetime_limit!=`events`.`datetime`';
$models=Users::model()->findAll($criteria);

这个异常被抛出CActiveFinder::getColumnSelect https://github.com/yiisoft/yii/blob/1.1.12/framework/db/ar/CActiveFinder.php#L885.

When CDbCriteria::$select is a string, it's treated as a simple list of comma-delimited columns. Your expression gets interpreted as two distinct columns. You can work around this by setting select to an array yourself - in this case the comma splitting is not done¹:

$criteria = new CDbCriteria();
$criteria->select = array("DATE_ADD(NOW(), INTERVAL 5 DAY) AS datetime_limit");
$models = Users::model()->findAll($criteria);

请注意，如果您编写的别名与公共模型属性或数据库字段不对应，它将被检索但会默默地被忽略 - 由于某种原因，Yii 不会为此抛出异常。

¹ However, this function will still attempt to find a . in the expression and interpret the part after it as a column identifier - don't use . in your expression and you should be fine.