Question

我已经在一个SQL查询中编写了它并且工作正常。我如何在 codeigniter 中写这个？

$sql = "SELECT * 
         FROM single_message
         WHERE 
           ( school_id='$schoolId' AND 
             classId='$classId' AND 
             sectionId='$sectionId' AND 
             sender_id='$senderId' AND 
             receiver_id ='$receiverId'
           ) OR 
           ( chool_id='$schoolId' AND 
             classId='$classId' AND
             sectionId='$sectionId' AND
             sender_id='$receiverId' AND
             receiver_id ='$senderId'
           )
        ORDER BY messageId DESC"`;

这是我尝试过的：

$condition = array(
                'school_id' => $schoolId,
                'classId' => $classId,
                'sectionId' => $sectionId,
                'sender_id' => $senderId,
                'receiver_id' => $receiverId
            );

$this->db->select('*');
$this->db->where($condition);
return $this->db->get('single_message')->result_array();

Answer 1

根据您的SQL查询：

$sql = "SELECT * FROM single_message WHERE (school_id='$schoolId' AND classId='$classId' AND sectionId='$sectionId' AND sender_id='$senderId' AND receiver_id ='$receiverId') OR (chool_id='$schoolId' AND classId='$classId' AND sectionId='$sectionId' AND sender_id='$receiverId' AND receiver_id ='$senderId') ORDER BY messageId DESC";

有两种方法可以编写查询。我将逐一解释：

解决方案1： 您可以简单地将条件放在where子句中，如下所述 - ＆gt;

$condition = "(school_id='$schoolId' AND classId='$classId' AND sectionId='$sectionId' AND sender_id='$senderId' AND receiver_id ='$receiverId') OR (chool_id='$schoolId' AND classId='$classId' AND sectionId='$sectionId' AND sender_id='$receiverId' AND receiver_id ='$senderId')";

        $this->db->select('*');
        $this->db->where($condition);
        return $this->db->get('single_message')->result_array();

在这里你可以看到我已经完成了以字符串格式传递条件的地方。这是fisrt解决方案。编写此查询的另一种方法是。

解决方案第二： 查询分组 - ＆gt;它允许您通过将它们括在括号中来创建WHERE子句组。所以查询就像：

$condition['AND'] = array(
        'school_id' => $schoolId,
        'classId' => $classId,
        'sectionId' => $sectionId,
        'sender_id' => $senderId,
        'receiver_id' => $receiverId
    );
    $condition['OR'] = array(
        'school_id' => $schoolId,
        'classId' => $classId,
        'sectionId' => $sectionId,
        'sender_id' => $receiverId,
        'receiver_id' => $senderId
    );

    $this->db->select('*');

    // Starts first group
    $this->db->group_start();

// AND condition placed in below line
    $this->db->where($condition['AND']);

// First group ends here
    $this->db->group_end();

// Another group has been started here for OR clause
    $this->db->or_group_start();

// Here we placed our OR codition
    $this->db->where($condition['OR']);

// Second group ends here
    $this->db->group_end();

return $this->db->get('single_message')->result_array();

它将产生您需要的确切结果。如果您有任何疑问，请告诉我。有关更多详细信息，请在此处阅读查询生成器说明：Query Grouping

Answer 2

将第二个参数作为null传递，将第三个参数作为false传递将无法转发您的查询。

试用此代码：

$this->db->select('*');
$this->db->where("school_id='$schoolId' AND classId='$classId' AND sectionId='$sectionId' AND sender_id='$senderId' AND receiver_id ='$receiverId') OR (chool_id='$schoolId' AND classId='$classId' AND sectionId='$sectionId' AND sender_id='$receiverId' AND receiver_id ='$senderId'", null, false);
$this->db->order_by("messageId", "desc");
$this->db->get();

以下是codeigniter文档中的Where reference。

如何编写AND OR条件codeigniter

2 个答案: