问题描述

我有国家数据库表(就像在指南中找到的一样

I have country database table (like found in the guide) that I test yii2 development application. I have field population and I want to create a public method in Country model to return all countries of specific population limits. i.e return all countries of population between x and y.

我尝试了以下方法:

// models/Country.php
....

public function getPopulationBetween($lower, $upper)
{
  return Country::findAll(['population' => [">=".$lower, "<=".$upper]]);

}

在 CountryController 中:

In the CountryController:

public function actionGetBetween($lower, $upper)
    {
      print_r(Country::getPopulationBetween($lower, $upper));
    }

它返回一个空数组 i,e Array()

It returns an empty array i,e Array ()

现在我需要知道如何将 findAll 的条件设置为类似于 SQL 条件 ... Where population >= 20000 AND population <= 40000000即如何使用数组添加对条件的比较?！

Now I need to know how to set the condition of findAll to be like the SQL condition ... Where population >= 20000 AND population <= 40000000 i.e How to add comparison to the condition with using an array?!

另一个侧面 - 或可选 - 问题， 为什么在 Country.php 中调用 findAll 如下:

Another side -or optional- question, Why in Country.php when calling findAll as follows:

public function getPopulationBetween($lower, $upper)
    {
      return $this->findAll(['population' => [">=".$lower, "<=".$upper]]);

    }

它返回一个错误:

未知方法 – yiiaseUnknownMethodException

调用未知方法:appcontrollersCountryController::findAll()

Calling unknown method: appcontrollersCountryController::findAll()

换句话说，为什么它必须静态调用?

In other words why must it called statically?

推荐答案

使用调试模块查看生成的 SQL 查询.

Use debug module to see the generated SQL query.

就您而言，它将是:

SELECT * FROM `countries` WHERE `population` IN ('>=20000', '<=40000000')

如你所见，这绝对是错误的.

As you can see it's definitely wrong.

检查findAll()，不适合这种情况.改用 find().

Check the documentation for findAll(), it's not suitable for such condition. Use find() instead.

1)

public static function getPopulationBetween($lower, $upper)
{
    return Country::find()
        ->where(['and', "population>=$lower", "id<=$upper"])
        ->all();
}

请注意，在这种情况下，不会应用引用和转义.

Note that in this case quoting and escaping won't be applied.

2)

public static function getPopulationBetween($lower, $upper)
{
    return Country::find()
        ->where(['>=', 'population', $lower])
        ->andWhere(['<=', 'population', $upper])
        ->all();
}

还将方法的声明更改为static，因为它不依赖于对象实例.

Also change declaration of the method to static since it's not dependent on object instance.

请阅读这个和本部分官方文档了解查询的 where 部分是如何构造的.

Please read this and this sections of official documentation to understand how where part of query is constructed.

也许把这个方法放在自定义的查询类中会更好.你可以阅读这里.

Maybe it's better to put this method in customized query class. You can read about it here.

您的其他问题的答案:您不应在对象上下文中调用 findAll()，因为它是框架设计的静态方法.

The answer for your additional question: you should not call findAll() in object context because it's static method by framework design.

检查yiidbBaseActiveRecord:

public static function findAll($condition)

这篇关于yii2 BaseActiveRecord findAll() 条件大于或小于的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！