标签：mysql aggregate group-concat
我从通用问题/答案数据中获取名称和地址数据,以创建某种规范化的报告数据库.
我得到的查询使用group_concat,适用于各个问题集,但不适用于多个集合.
我试图通过仅使用forename和surname以及仅3条记录来简化我正在做的事情,2个用于1个人,1个用于另一个.实际上,虽然有超过300,000条记录.
qs.Id = 1的结果为Example.
QuestionSetId Forename Surname
-------------------------------------------------------
1 Bob Jones
Example的结果与qs.Id IN(1,2,3).
QuestionSetId Forename Surname
-------------------------------------------------------
3 Bob,Bob,Frank Jones,Jones,Smith
我希望看到qs.Id IN(1,2,3).
QuestionSetId Forename Surname
-------------------------------------------------------
1 Bob Jones
2 Bob Jones
3 Frank Smith
那么如何让第二个示例为每组名称和地址信息返回一个单独的行？
我意识到数据存储的当前方式是“有问题的”,但我无法改变数据的存储方式.
我可以得到sets of individual answers,但不知道如何结合其他人.
我简化的Schema,我无法改变：
CREATE TABLE StaticQuestion (
Id INT NOT NULL,
StaticText VARCHAR(500) NOT NULL);
CREATE TABLE Question (
Id INT NOT NULL,
Text VARCHAR(500) NOT NULL);
CREATE TABLE StaticQuestionQuestionLink (
Id INT NOT NULL,
StaticQuestionId INT NOT NULL,
QuestionId INT NOT NULL,
DateEffective DATETIME NOT NULL);
CREATE TABLE Answer (
Id INT NOT NULL,
Text VARCHAR(500) NOT NULL);
CREATE TABLE QuestionSet (
Id INT NOT NULL,
DateEffective DATETIME NOT NULL);
CREATE TABLE QuestionAnswerLink (
Id INT NOT NULL,
QuestionSetId INT NOT NULL,
QuestionId INT NOT NULL,
AnswerId INT NOT NULL,
StaticQuestionId INT NOT NULL);
仅有forename和surname的一些示例数据.
INSERT INTO StaticQuestion (Id, StaticText)
VALUES (1, 'FirstName'),
(2, 'LastName');
INSERT INTO Question (Id, Text)
VALUES (1, 'What is your first name?'),
(2, 'What is your forename?'),
(3, 'What is your Surname?');
INSERT INTO StaticQuestionQuestionLink (Id, StaticQuestionId, QuestionId, DateEffective)
VALUES (1, 1, 1, '2001-01-01'),
(2, 1, 2, '2008-08-08'),
(3, 2, 3, '2001-01-01');
INSERT INTO Answer (Id, Text)
VALUES (1, 'Bob'),
(2, 'Jones'),
(3, 'Bob'),
(4, 'Jones'),
(5, 'Frank'),
(6, 'Smith');
INSERT INTO QuestionSet (Id, DateEffective)
VALUES (1, '2002-03-25'),
(2, '2009-05-05'),
(3, '2009-08-06');
INSERT INTO QuestionAnswerLink (Id, QuestionSetId, QuestionId, AnswerId, StaticQuestionId)
VALUES (1, 1, 1, 1, 1),
(2, 1, 3, 2, 2),
(3, 2, 2, 3, 1),
(4, 2, 3, 4, 2),
(5, 3, 2, 5, 1),
(6, 3, 3, 6, 2);
以防SQLFiddle在这里是我链接到的示例中的3个查询：
1： – 工作查询但仅限于1组数据.
SELECT MAX(QuestionSetId) AS QuestionSetId,
GROUP_CONCAT(Forename) AS Forename,
GROUP_CONCAT(Surname) AS Surname
FROM (SELECT
x.QuestionSetId,
CASE x.StaticQuestionId WHEN 1 THEN Text END AS Forename,
CASE x.StaticQuestionId WHEN 2 THEN Text END AS Surname
FROM (SELECT (SELECT link.StaticQuestionId
FROM StaticQuestionQuestionLink link
WHERE link.Id = qa.QuestionId
AND link.DateEffective <= qs.DateEffective
AND link.StaticQuestionId IN (1, 2)
ORDER BY link.DateEffective DESC LIMIT 1) AS StaticQuestionId,
a.Text,
qa.QuestionSetId
FROM QuestionSet qs
INNER JOIN QuestionAnswerLink qa ON qs.Id = qa.QuestionSetId
INNER JOIN Answer a ON qa.AnswerId = a.Id
WHERE qs.Id IN (1)) x) y
2： – 工作查询但在多组数据上产生不良结果.
SELECT MAX(QuestionSetId) AS QuestionSetId,
GROUP_CONCAT(Forename) AS Forename,
GROUP_CONCAT(Surname) AS Surname
FROM (SELECT
x.QuestionSetId,
CASE x.StaticQuestionId WHEN 1 THEN Text END AS Forename,
CASE x.StaticQuestionId WHEN 2 THEN Text END AS Surname
FROM (SELECT (SELECT link.StaticQuestionId
FROM StaticQuestionQuestionLink link
WHERE link.Id = qa.QuestionId
AND link.DateEffective <= qs.DateEffective
AND link.StaticQuestionId IN (1, 2)
ORDER BY link.DateEffective DESC LIMIT 1) AS StaticQuestionId,
a.Text,
qa.QuestionSetId
FROM QuestionSet qs
INNER JOIN QuestionAnswerLink qa ON qs.Id = qa.QuestionSetId
INNER JOIN Answer a ON qa.AnswerId = a.Id
WHERE qs.Id IN (1, 2, 3)) x) y
3： – 仅在1个字段(答案)上对多组数据进行工作查询.
SELECT
qs.Id AS QuestionSet,
a.Text AS Answer
FROM
QuestionSet qs
INNER JOIN QuestionAnswerLink qalink ON qs.Id = qalink.QuestionSetId
INNER JOIN StaticQuestionQuestionLink sqqlink ON qalink.QuestionId = sqqlink.QuestionId
INNER JOIN Answer a ON qalink.AnswerId = a.Id
WHERE
sqqlink.StaticQuestionId = 1 /* FirstName */
AND sqqlink.DateEffective =
(SELECT DateEffective
FROM StaticQuestionQuestionLink
WHERE StaticQuestionId = 1
AND DateEffective <= qs.DateEffective
ORDER BY DateEffective
DESC
LIMIT 1)
解决方法:
从@PixelMaker和@PeteGO窃取,我将把这个扔进去
SELECT qs.Id AS QuestionSetId,
GROUP_CONCAT(a.Text order by a.id) AS Answer
FROM QuestionSet qs
JOIN QuestionAnswerLink qa ON qs.Id = qa.QuestionSetId
JOIN StaticQuestionQuestionLink link ON qa.QuestionId = link.QuestionId
JOIN Answer a ON qa.AnswerId = a.Id
WHERE link.Id = qa.QuestionId
AND link.DateEffective <= qs.DateEffective
AND link.StaticQuestionId IN (1, 2)
and qs.id in (1,2,3)
GROUP BY qs.Id
最后这一个SQL Fiddle
SELECT qs.Id AS QuestionSetId,
GROUP_CONCAT(case link.staticquestionid when 1 then a.Text end) AS forename,
GROUP_CONCAT(case link.staticquestionid when 2 then a.Text end) AS surname
FROM QuestionSet qs
JOIN QuestionAnswerLink qa ON qs.Id = qa.QuestionSetId
JOIN StaticQuestionQuestionLink link ON qa.QuestionId = link.QuestionId
JOIN Answer a ON qa.AnswerId = a.Id
WHERE link.Id = qa.QuestionId
AND link.DateEffective <= qs.DateEffective
AND link.StaticQuestionId IN (1, 2)
and qs.id in (1,2,3)
GROUP BY qs.Id
这给出了期望的结果.
标签：mysql,aggregate,group-concat 来源： https://codeday.me/bug/20190620/1246533.html
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