問題描述
MySQL：對 GROUP_CONCAT 值進行排序 (MySQL: Sort GROUP_CONCAT values)
In short: Is there any way to sort the values in a GROUP_CONCAT statement?
Query:
GROUP_CONCAT((SELECT GROUP_CONCAT(parent.name SEPARATOR " » ")
FROM test_competence AS node, test_competence AS parent
WHERE node.lft BETWEEN parent.lft AND parent.rgt
AND node.id = l.competence
AND parent.id != 1
ORDER BY parent.lft) SEPARATOR "<br />\n") AS competences
I get this row:
Crafts » Joinery
Administration » Organization
I want it like this:
Administration » Organization
Crafts » Joinery
參考解法
方法 1:
Sure, see http://dev.mysql.com/doc/refman/...tions.html#function_group-concat:
SELECT student_name,
GROUP_CONCAT(DISTINCT test_score ORDER BY test_score DESC SEPARATOR ' ')
FROM student
GROUP BY student_name;
方法 2:
Do you mean to order by?
SELECT _key,
COUNT(*) as cnt,
GROUP_CONCAT(_value ORDER BY _value SEPARATOR ', ') as value_list
FROM group_concat_test
GROUP BY _key
ORDER BY _key;