MYSQL DISTINCT ORDER BY没有给出正确的顺序

时间:2012-01-21 11:56:57

标签: mysql sql-order-by distinct expressionengine

更新:感谢大家,使用此查询现在100%正常工作:

SELECT e.entry_id
FROM exp_channel_titles AS e
INNER JOIN exp_matrix_data AS m ON m.entry_id = e.entry_id
WHERE e.channel_id = 2
GROUP BY e.entry_id
ORDER BY MIN(m.col_id_2) ASC

这是我的代码。

来自.home_laagste_rentes的代码

{exp:channel:entries dynamic="no" fixed_order="0{embed:entry_ids}" disable="member_data|pagination|categories"}
<tr class="{switch="odd|even"}">
    <td><a href="#" title="{title}">{title}</a></td>
    <td>{dk:lowest col="rente" decimals="2" dec_point=","}%</td>
    <td>{count}</td>
</tr>
{/exp:channel:entries}

来自页面的代码:

<table id="rowspan" cellspacing="0" class="tablesorter">
<thead>
    <tr>
        <th>Krediet aanbieder</th>
            <th>Rente</th>
            <th>Beoordeling</th>
    </tr>
</thead>
<tbody>
{embed="embeds/.home_laagste_rentes"
entry_ids="{exp:query sql="
    SELECT DISTINCT (e.entry_id)
    FROM exp_channel_titles AS e
    INNER JOIN exp_matrix_data AS m ON m.entry_id = e.entry_id
    WHERE e.channel_id = 2
    ORDER BY m.col_id_2 ASC
"}|{entry_id}{/exp:query}"}
</tbody>

col_id_2设置为十进制(10,4)

entry_id设置为int

这是过滤重复项,但它没有给出正确的顺序。看起来过滤重复是随机完成的...请参阅此链接以获取输出: http://postimage.org/image/9vzahuuez/

2 个答案:

答案 0 :(得分:1)

对于一个m.col_id_2,您有许多(可能不同的)e.entry_id值。

您的查询甚至不是有效的ANSI SQL,因为在ORDER BY之后评估DISTINCT,因此ORDER BY m.col_id_2应该创建错误(如果您的MySQL设置是严格的ANSI SQL)。

解决方案是使用GROUP BY代替SELECT DISTINCT来说明应该使用哪个值进行排序:

SELECT e.entry_id
FROM exp_channel_titles AS e
INNER JOIN exp_matrix_data AS m ON m.entry_id = e.entry_id
WHERE e.channel_id = 2
GROUP BY e.entry_id
ORDER BY MAX(m.col_id_2) ASC                  --- or MIN(), or AVG()

答案 1 :(得分:0)

我不知道您桌子的SCHEMA,但您可以尝试此查询。

SELECT iTable.entry_id
FROM
    (SELECT DISTINCT e.entry_id, m.col_id_2
    FROM exp_channel_titles AS e INNER JOIN exp_matrix_data AS m 
                ON m.entry_id = e.entry_id
    WHERE e.channel_id = 2) as iTable
ORDER BY iTable.col_id_2 ASC