我有以下查询:
SELECT *, RES.res_id 'ID', RES.RES_Title 'Title',
GROUP_CONCAT(DISTINCT T.T_Name separator ', ') 'Topics',
GROUP_CONCAT(DISTINCT CH.CH_Code separator ', ') 'Chapters'
FROM Resources RES
LEFT JOIN topic_to_resource RT ON RT.RT_ResourceID = RES.RES_ID
LEFT JOIN topics T on T.T_ID = RT.RT_TopicID
LEFT JOIN topic_to_chapter TCH on TCH.TCH_TopicID = T.T_ID
LEFT JOIN chapters CH ON CH.CH_ID = TCH.TCH_FrameworkID
WHERE RES_Status = 'Active'
GROUP BY RES.RES_ID
ORDER BY RES_Title ASC, RES_Source DESC LIMIT 0, 10
对于每个GROUP_CONCAT(主题和章节),我需要将列表转换为链接,同时保持Distinct。
例如,代替上述查询的主题输出:体育,时事,政治,气候等
我需要生成:
<a href="page.asp?topic=Sports" title="Sports">Sports</a>,
<a href="page.asp?topic=Current%20Events" title="Current Events">Current Events</a>,
<a href="page.asp?topic=Politics" title="Politics">Politics</a>,
<a href="page.asp?topic=Climate" title="Climate">Climate</a>
我可以通过在GROUP_CONCAT中嵌套CONCAT来实现链接,但后来我失去了Distinct。此外,我需要查询保持按资源ID(RES.RES_ID)分组。
关于如何完成不同主题和章节的链接列表的任何想法?
非常感谢提前!
答案 0 :(得分:0)
从this question开始,并使用该查询作为以下示例的基础,您可以执行以下操作:
SELECT
CONCAT(res_id,': ',res_name) 'Resources',
GROUP_CONCAT(distinct t_name order by t_id separator ',') 'Topics',
GROUP_CONCAT(distinct ch_name order by ch_id separator ',') 'Chapters'
FROM (SELECT res_id,
res_name,
t_id,
t_name,
ch_id,
CONCAT("<a href=\"page.asp?topic=",ch_name,"\" title=\"",ch_name,"\">",ch_name,"</a>") as ch_name
FROM resources r
JOIN topics_to_resource ttr ON ttr.tr_resid = r.res_id
JOIN topics t on t.t_id = ttr.tr_tid
JOIN topics_to_chapter ttc on ttc.tch_tid = t.t_id
JOIN chapters ch ON ch.ch_id = tch_chid) links
GROUP BY res_id
ORDER BY res_id, t_id, ch_id;
基本上我已将源数据包装在单独的(子)查询中,构建链接,然后在此之外执行GROUP_CONCAT
。
这会产生:
<a href="page.asp?topic=CHAPTER #1" title="CHAPTER #1">CHAPTER #1</a>,
<a href="page.asp?topic=CHAPTER #2" title="CHAPTER #2">CHAPTER #2</a>,
<a href="page.asp?topic=CHAPTER #3" title="CHAPTER #3">CHAPTER #3</a>
有关详细信息,请参阅this fiddle