Mysql 无条件群Concat
我正试图重写我的查询以使用列而不是行。我有一个疑问:Mysql 无条件群Concat,mysql,group-concat,Mysql,Group Concat,我正试图重写我的查询以使用列而不是行。我有一个疑问: mysql> SELECT r.id as responseId, a.id as answerId, o.id, optionId, q.label as questionLabel, o.label as optionLabel -> FROM answer a -> INNER JOIN question q ON questionId = q.id -> INNER JOIN answe
mysql> SELECT r.id as responseId, a.id as answerId, o.id, optionId, q.label as questionLabel, o.label as optionLabel
-> FROM answer a
-> INNER JOIN question q ON questionId = q.id
-> INNER JOIN answer_options_option ao ON a.id = ao.answerId
-> INNER JOIN `option` o ON ao.optionId = o.id
-> INNER JOIN response r ON a.responseId = r.id
-> ORDER BY r.id, a.id, o.id;
mysql> SELECT r.id as responseId,
-> IF(q.label = 'Q1', GROUP_CONCAT(o.label), NULL) as Q1,
-> IF(q.label = 'Q2', GROUP_CONCAT(o.label), NULL) as Q2
-> FROM answer a
-> INNER JOIN question q ON questionId = q.id
-> INNER JOIN answer_options_option ao ON a.id = ao.answerId
-> INNER JOIN `option` o ON ao.optionId = o.id
-> INNER JOIN response r ON a.responseId = r.id
-> GROUP BY r.id;
这给了我这个输出:
+------------+----------+----+----------+---------------+-------------+
| responseId | answerId | id | optionId | questionLabel | optionLabel |
+------------+----------+----+----------+---------------+-------------+
| 1 | 1 | 2 | 2 | Q1 | no |
| 1 | 2 | 4 | 4 | Q2 | b |
| 2 | 3 | 1 | 1 | Q1 | yes |
| 2 | 4 | 3 | 3 | Q2 | a |
| 2 | 4 | 4 | 4 | Q2 | b |
| 2 | 4 | 5 | 5 | Q2 | c |
+------------+----------+----+----------+---------------+-------------+
+------------+-----------+-------+
| responseId | Q1 | Q2 |
+------------+-----------+-------+
| 1 | no | b |
| 2 | yes | a,b,c |
+------------+-----------+-------+
但我希望得到以下输出:
+------------+----------+----+----------+---------------+-------------+
| responseId | answerId | id | optionId | questionLabel | optionLabel |
+------------+----------+----+----------+---------------+-------------+
| 1 | 1 | 2 | 2 | Q1 | no |
| 1 | 2 | 4 | 4 | Q2 | b |
| 2 | 3 | 1 | 1 | Q1 | yes |
| 2 | 4 | 3 | 3 | Q2 | a |
| 2 | 4 | 4 | 4 | Q2 | b |
| 2 | 4 | 5 | 5 | Q2 | c |
+------------+----------+----+----------+---------------+-------------+
+------------+-----------+-------+
| responseId | Q1 | Q2 |
+------------+-----------+-------+
| 1 | no | b |
| 2 | yes | a,b,c |
+------------+-----------+-------+
所以我提出了这个问题:
mysql> SELECT r.id as responseId, a.id as answerId, o.id, optionId, q.label as questionLabel, o.label as optionLabel
-> FROM answer a
-> INNER JOIN question q ON questionId = q.id
-> INNER JOIN answer_options_option ao ON a.id = ao.answerId
-> INNER JOIN `option` o ON ao.optionId = o.id
-> INNER JOIN response r ON a.responseId = r.id
-> ORDER BY r.id, a.id, o.id;
mysql> SELECT r.id as responseId,
-> IF(q.label = 'Q1', GROUP_CONCAT(o.label), NULL) as Q1,
-> IF(q.label = 'Q2', GROUP_CONCAT(o.label), NULL) as Q2
-> FROM answer a
-> INNER JOIN question q ON questionId = q.id
-> INNER JOIN answer_options_option ao ON a.id = ao.answerId
-> INNER JOIN `option` o ON ao.optionId = o.id
-> INNER JOIN response r ON a.responseId = r.id
-> GROUP BY r.id;
但是它给了我这个输出:
+------------+-----------+------+
| responseId | Q1 | Q2 |
+------------+-----------+------+
| 1 | no,b | NULL |
| 2 | yes,a,b,c | NULL |
+------------+-----------+------+
甚至可以这样使用GROUP\u CONCAT
?有没有其他方法来完成我想做的事情
这里有一个。您需要将
组\u CONCAT
移动到条件之外,以便根据问题聚合选项,而不仅仅是根据问题值获得整个聚合结果:
SELECT r.id as responseId,
GROUP_CONCAT(CASE WHEN q.label = 'Q1' THEN o.label END ORDER BY o.label) as Q1,
GROUP_CONCAT(CASE WHEN q.label = 'Q2' THEN o.label END ORDER BY o.label) as Q2
FROM answer a
INNER JOIN question q ON questionId = q.id
INNER JOIN answer_options_option ao ON a.id = ao.answerId
INNER JOIN `option` o ON ao.optionId = o.id
INNER JOIN response r ON a.responseId = r.id
GROUP BY r.id;
输出:
responseId Q1 Q2
1 no b
2 yes a,b,c
感谢您提供小提琴。这使得回答这个问题变得容易多了。