本文介绍了我们可以对 group_concat(distinct somefield) 进行 DISTINCT 吗?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
http://sqlfiddle.com/#!2/37dd94/17
如果我执行 SELECT DISTINCT，我会得到与仅执行 SELECT 相同的结果.
If I do SELECT DISTINCT I get the same results as doing just SELECT.
在查询结果中，您将看到两个包含Evora"区的活动.只有一个应该出现.
On the query results, you will see two activities that contains the District "Evora". Only one should appear.
有什么线索吗?
推荐答案
下面的查询怎么样 (SQL FIDDLE):
How about the following query (SQL FIDDLE):
SELECT GROUP_CONCAT(APA_T.district), t.name
FROM tbl_activity AS t
JOIN tbl_activity_package AS ap ON t.id = ap.id_activity
JOIN
(
SELECT DISTINCT apa.district AS district,
(
SELECT s1.id_activity_package
FROM tbl_activity_package_address s1
WHERE apa.district = s1.district
ORDER BY s1.id DESC
LIMIT 1
) AS idActivityPackage
FROM
tbl_activity_package_address apa
ORDER BY apa.district
) AS APA_T
ON ap.id = APA_T.idActivityPackage
GROUP BY t.name
ORDER BY APA_T.district;
上面的查询会去掉多余的Faro和Evora.
The above query will eliminate the extra Faro and Evora.
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