Question

所以我想知道这是否是管理此表数据的最佳方式，因为我的查询得不到我想要的正确结果。

我希望它能从表格中的最后一个日期条目中获得前5名排名。问题是如果character_id为0。当我执行我的php以查看是否没有值时，它应该回显TBD，但它仍然没有在数组中显示为0。

表：top5

id    ranking #    character_id    status_id    date_created
1         1           1                1         2011-10-17 17:18:54 
2         2           2                1         2011-10-17 17:18:54    
3         3           3                1         2011-10-17 17:18:54
4         4           4                1         2011-10-17 17:18:54
5         5           5                1         2011-10-17 17:18:54
6         1           6                1         2011-10-24 12:18:54
7         2           7                1         2011-10-24 12:18:54
8         3           8                1         2011-10-24 12:18:54
9         4           9                1         2011-10-24 12:18:54
10        5           0                1         2011-10-24 12:18:54

function getTop5()
{
    $this->db->select('characters.character_name, top5.character_id'); 
    $this->db->from('top5'); 
    $this->db->join('characters', 'characters.id = top5.character_id'); 
    $this->db->where('top5.status_id', '1');  
    $this->db->order_by('top5.date_created','desc');
    $this->db->limit(5);
    $query = $this->db->get();
    return $query->result_array();
}

Array ( [0] => 
       Array ( [character_name] => \"Mr. Magnificent\" Matt Sharp 
               [character_id] => 9 ) 
        [1] => 
       Array ( [character_name] => \"The Unforgettable\" Jimmy Watkins 
               [character_id] => 8 ) 
        [2] => 
       Array ( [character_name] => Romie Rains 
               [character_id] => 7 ) 
        [3] => 
       Array ( [character_name] => Monica Dawson 
               [character_id] => 6 ) 
        [4] => 
       Array ( [character_name] => \"The Outlaw\" Mike Mayhem 
               [character_id] => 5 ) )

编辑：其他人想尝试一下吗？

如此迷失，仍然无法获得理想的结果

Answer 1

不确定它是什么db类，只是附加

AND date(date_created) = CURDATE();

查询

或将DESC追加到ORDER子句

类似

$this->db->select('characters.character_name, top5.character_id'); 
$this->db->from('top5'); 
$this->db->join('characters', 'characters.id = top5.character_id'); 
$this->db->where('top5.status_id', '1'); 
// WHERE date(top5.date_created) = CURDATE() 
$this->db->order_by('top5.date_created');
$this->db->limit(5);
$query = $this->db->get();

Answer 2

您希望按top5.date_created降序排序。如果你真的只想要最后一天，那么你也需要一个WHERE条件。

Answer 3

function getTop5()
{
    $this->db->select('characters.character_name, top5.character_id'); 
    $this->db->from('top5'); 
    $this->db->join('characters', 'characters.id = top5.character_id'); 
    $this->db->join( '( SELECT DATE(MAX(date_created)) AS lastdate
                        FROM top5 
                        WHERE status_id = 1
                      ) AS tm'
                   , 'top5.created_at >= tm.lastdate 
                      AND top5.created_at < tm.lastdate + INTERVAL 1 DAY'); 
    $this->db->where('top5.status_id', '1'); 
    $this->db->order_by('top5.ranking','asc');
    $this->db->limit(5);
    $query = $this->db->get();
    return $query->result_array();
}

排名前5位的问题

3 个答案: