Mysql 如何在Active Records Designer中进行多重加入

大家好，你们能帮我一下吗？我是数据库和Codeigniter的初学者。 如何在活动记录中编写此多个内部联接和左联接查询

SELECT suppliers.*, category.strCategory, category_1.strCategory AS strParent, 
tblcitylist.city_name
FROM ((suppliers INNER JOIN category ON suppliers.intCat=Category.intId) INNER JOIN tblcitylist ON 
suppliers.intCity=tblcitylist.city_id) LEFT JOIN category AS category_1 ON 
category.intParent=Category_1.intId
WHERE status='y';

我有三个表供应商，tblcitylist和类别。要获取具有intCat和intCity的供应商的数据，结果是具有城市名称（城市名称）和类别名称（strCategory）的供应商表的数据。

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谢谢

在这种情况下，使用直接SQL似乎更简单。更不用说它执行得更快了

$sql = "SELECT........";
$query = $this->db->query($sql);

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这似乎是一种使用直接SQL更简单的情况。更不用说它执行得更快了

$sql = "SELECT........";
$query = $this->db->query($sql);

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也许这就是你想要的

$query = $this->db->select('suppliers.*, category.strCategory, category_1.strCategory AS strParent, tblcitylist.city_name')
            ->from('suppliers')
            ->join('category',                  'suppliers.intCat=Category.intId',          'inner')
            ->join('tblcitylist',               'suppliers.intCity=tblcitylist.city_id',    'inner')
            ->join('category as `category_1',   'category.intParent=Category_1.intId',      'left')
            ->where('status','y')
                ->get();

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CI DB文档：

也许这就是你想要的

$query = $this->db->select('suppliers.*, category.strCategory, category_1.strCategory AS strParent, tblcitylist.city_name')
            ->from('suppliers')
            ->join('category',                  'suppliers.intCat=Category.intId',          'inner')
            ->join('tblcitylist',               'suppliers.intCity=tblcitylist.city_id',    'inner')
            ->join('category as `category_1',   'category.intParent=Category_1.intId',      'left')
            ->where('status','y')
                ->get();

CI DB文档：