Question

我在以下问题上遇到了一些麻烦，会告诉你我有什么，我想要什么以及我尝试过什么......

我想要的是：我有一个父表和子表，父表是

访问

，子表是

评估

，两者之间定义了一对多的关系，见下面的表结构：

SELECT
VisitPk, (Primary Key)
ClientFk,
ClientSiteFk,
AssessorFk,
VisitStartDate,
VisitEndDate,
CONCAT(MONTHNAME(TargetDate), ' ', YEAR(TargetDate)) AS TargetMonth,
Duration,
VisitStatus,
TargetDate,
`Long`,
Lat,
VisitPlanRequired,
VisitPlanIssued,
VisitPlanStatus,
VisitPlanAttachment,
DATE_SUB(VisitStartDate, INTERVAL 1 Month) AS VisitPlanDue,
Overnight,
YEAR(TargetDate) AS `Year`
FROM visits
ORDER BY YEAR(TargetDate) DESC, TargetDate, VisitStartDate

和

SELECT
assessments.AssessmentPk, (Foreign Key)
assessments.VisitFk,
assessments.`Scope`,
FROM assessments

我需要的是将一个字段放入评估表中，以便它从访问表中查找所有范围，然后对它们进行分组。 E.G是访问pk 1有两个条目3个子记录，1,2和3，id喜欢使用concat / implode函数在父表中将其显示为1,2,3。

我可以用PHP做到这一点并将数据物理存储在表中，但我宁愿不沿着这条路走下去。

我已尝试在第一个select语句中使用第二个select语句来运行子查询但是甚至没有接近。

我也尝试过使用这个例子：Can I concatenate multiple MySQL rows into one field?，例如：

SELECT person_id, GROUP_CONCAT(hobbies SEPARATOR ', ')
FROM peoples_hobbies GROUP BY person_id

最终，我需要的是有人告诉我如何使用上面的group_contact示例放置第二个选择语句，但是查找子表，其中assessmentfk = assessmentpk。

类似于：

SELECT
VisitPk, (Primary Key)
ClientFk,
ClientSiteFk,
**CONCAT(SELECT `scope` from assessments LEFT OUTER JOIN assessments ON visits.VisitPk = assessments.VisitFk) as `Scope`**
AssessorFk,
VisitStartDate,
VisitEndDate,
CONCAT(MONTHNAME(TargetDate), ' ', YEAR(TargetDate)) AS TargetMonth,
Duration,
VisitStatus,
TargetDate,
`Long`,
Lat,
VisitPlanRequired,
VisitPlanIssued,
VisitPlanStatus,
VisitPlanAttachment,
DATE_SUB(VisitStartDate, INTERVAL 1 Month) AS VisitPlanDue,
Overnight,
YEAR(TargetDate) AS `Year`
FROM visits
ORDER BY YEAR(TargetDate) DESC, TargetDate, VisitStartDate

我希望这是有道理的，有人可以提供帮助，这远远超出了我过去所做的任何事情，所以提前道歉。

Answer 1

尝试两个表的内连接和

分组

      SELECT 
            VisitPk, ClientFk, ClientSiteFk,AssessorFk,VisitStartDate, VisitEndDate,
            GROUP_CONCAT(a.scope, ',') as scopes
            CONCAT(MONTHNAME(TargetDate), ' ', YEAR(TargetDate)) AS TargetMonth,
            Duration,VisitStatus,TargetDate,`Long`,Lat,VisitPlanRequired,
            VisitPlanIssued,VisitPlanStatus,VisitPlanAttachment,
            DATE_SUB(VisitStartDate, INTERVAL 1 Month) AS VisitPlanDue,
            Overnight,YEAR(TargetDate) AS `Year`
     FROM visits v
     INNER JOIN assessments a
     ON v.VisitPk = a. VisitFk
     GROUP BY v.VisitPk
     ORDER BY YEAR(TargetDate) DESC, TargetDate, VisitStartDate

为子表

1 个答案: