[英]Convert this MySQL Query to Codeigniter Active Record
我有两个桌子:
Dress (dress_id, title)
Dress_comment (comment_id, dress_id, comment)
我已经尝试了几个小时,无法将此查询转换为相应的Codeigniters的Active Class Record函数。
这是查询:
SELECT d.dress_id, d.title, COALESCE(dc.count, 0)
FROM dress d
JOIN (select dress_id, count(comment_id) as count from dress_comment group by dress_id) dc
ON d.dress_id = dc.dress_id
ORDER BY d.dress_id;
这是我到目前为止尝试过的:
//Creating the select subquery for the inner join
$this->db->select('dress_id, count(comment_id) as count')
->from('Dress_comment')
->group_by('dress_id')
->get();
$subQuery = $this->db->last_query();
//Main Query
$this->db->select('d.dress_id, d.title, COALESCE(dc.count,0)')
->from('Dress')
->join($subQuery . ' dc','dc.dress_id = d.dress_id','left')
->order_by('d.dress_id');
$result = $this->db->get();
return $result->result_array();
但是Codeigniter没有运行该查询,并且总是给出mysql语法错误。 Codeigniter将此活动方法转换为的sql格式为
SELECT `d`.`dress_id`, `d`.`title`, COALESCE(dc.count, `0)`
FROM (`Dress`) LEFT JOIN `SELECT` `dress_id`, count(comment_id) as count
FROM (`Dress_comment`)
GROUP BY `dress_id` dc
ON `dc`.`dress_id` = `d`.`dress_id`
ORDER BY `d`.`dress_id`
我能够在连接函数中使用mysql查询来解决此问题,如下所示:
$this->db->select('d.dress_id, d.title, dc.count as comments, dl.count as likes, dt.title, di.image_url')
->from('Dress d')
->join('(select dress_id, count(comment_id) as count from dress_comment group by dress_id) dc','dc.dress_id = d.dress_id','left')
->order_by('d.dress_id');
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