如何在此查询的 codeigniter 活动记录中编写子查询

Posted 2023-05-08

【中文标题】如何在此查询的 codeigniter 活动记录中编写子查询

【英文标题】：How to write Subquery in codeigniter active record for this query

【发布时间】：2016-01-08 05:51:05

【问题描述】：

 SELECT  from_id, (SELECT COUNT(id) FROM user_messages WHERE from_id=1223 AND status=1) AS sent_unread, 
    (SELECT COUNT(id) FROM user_messages WHERE from_id=1223 AND status=2) AS sent_read 
    FROM user_messages 
    WHERE from_id=1223 
    GROUP BY from_id

如何在CodeIgniter活动记录中编写上述select语句？

这是我想出的：

  $this->db->select('from_id, (SELECT COUNT(id) FROM user_messages WHERE from_id=1223 AND status=1) AS sent_unread,
        (SELECT COUNT(id) FROM user_messages WHERE from_id=1223 AND status=2) AS sent_read');

    $this->db->where('from_id', $member_id);

    $this->db->group_by('from_id');

    $this->db->from('user_messages');

    $result = $this->db->get();

    //echo $this->db->last_query();
    return $result->row();

这是正确的方法吗？

【参考方案1】：

试试这个

<?php
      $query="from_id, (SELECT COUNT(id) FROM user_messages WHERE from_id=1223 AND status=1) AS sent_unread,
            (SELECT COUNT(id) FROM user_messages WHERE from_id=1223 AND status=2) AS sent_read";
      $query_run=$this->db->select($query);
      $query_run->where('from_id', $member_id);
      $query_run->group_by('from_id');

      $result = $query_run->get('user_messages');
      //echo $this->db->last_query();
       return $result->row();
    ?>

【讨论】：

如果我们有两个查询怎么办？ @daular