Question

以下查询将输出显示为

Array ( [0] => stdClass Object ( [comment_ID] => 8 [ID] => 41 ) [1] => stdClass Object ( [comment_ID] => 12 [ID] => 35 ) [2] => stdClass Object ( [comment_ID] => 7 [ID] => 35 ) [3] => stdClass Object ( [comment_ID] => 5 [ID] => 35 ) )

我需要显示一个[ID}，其第一个[comment_ID]不需要2和第3个数据数组...而不是重复[ID]及其[comment_ID]我需要另一个[ID]的数据

function latest_post() {       

    $this->db->select('comment_ID, ID');
    $this->db->from('user_posts');
    $this->db->join('user_comments', 'comment_post_ID = ID');
    $this->db->where('post_status', 1);
    $this->db->where('comment_approved', 1);
    $this->db->where('comment_rate', 3);
    $this->db->order_by("ID", "desc");
    $this->db->limit(4);
    $query = $this->db->get();
    return $query->result();

}

Answer 1

使用group_by删除结果中的ID重复

$this->db->select('comment_ID, ID');
$this->db->from('user_posts');
$this->db->join('user_comments', 'comment_post_ID = ID');
$this->db->where('post_status', 1);
$this->db->where('comment_approved', 1);
$this->db->where('comment_rate', 3);
$this->db->group_by("ID");
$this->db->order_by("ID", "desc");
$this->db->limit(4);
$query = $this->db->get();
return $query->result();

这将导致每个ID的单个记录

Answer 2

使用连接时，请尝试始终在选择中定义表。

$query = $this->db->select('user_posts.comment_ID, user_posts.ID')
->from('user_posts')
->join('user_comments', 'user_comments.comment_post_ID = user_posts.ID')
->where('post_status', 1)
->where('comment_approved', 1)
->where('comment_rate', 3)
->order_by("ID", "desc")
->limit(4)
->get();
return $query->result();

另请注意，我删除了重复的$ this-＆gt; db

查询以使用where子句join和limit显示数据

2 个答案: