计算选择语句中的位置和位置

Question

嗨，我正在尝试在mysql中编写堆积的条形图，首先我需要正确查询，并且需要一些帮助。

目前我有：

SELECT
COUNT(TargetDate) AS Planned,
COUNT(StartDate) AS Completed,
MONTHNAME(TargetDate) AS `Month`,
StartDate,
AssessmentStatus
FROM AuditCycleAssessments
WHERE (Year(TargetDate) = Year(now()))
GROUP BY MONTHNAME(TargetDate)
ORDER BY Month(TargetDate)

效果很好，看起来像截图

但是我需要更改第三行以包括其自己的where语句，例如...

  (COUNT(StartDate) if AssessmentStatus=3) AS Completed,

因此，第一，有人可以帮助我实现这一目标。

谢谢

Answer 1

检查如何编写IF，但是如果要使用CASE，则无法写

SELECT
COUNT(TargetDate) AS Planned,
COUNT(CASE WHEN AssessmentStatus=3 THEN StartDate END) AS Completed,
MONTHNAME(TargetDate) AS `Month`,
StartDate,
AssessmentStatus
FROM AuditCycleAssessments
WHERE (Year(TargetDate) = Year(now()))
GROUP BY MONTHNAME(TargetDate)
ORDER BY Month(TargetDate)

Answer 2

使用CASE语句执行条件COUNT

SELECT
    COUNT(TargetDate) AS Planned,
    COUNT(CASE WHEN AssessmentStatus=3 THEN StartDate END) AS Completed,
    MONTHNAME(TargetDate) AS `Month`,
    StartDate,
    AssessmentStatus
FROM AuditCycleAssessments
WHERE (Year(TargetDate) = Year(now()))
GROUP BY MONTHNAME(TargetDate)
ORDER BY Month(TargetDate)

Answer 3

类似于以下内容的内容可能会为您服务，未经您的情况测试，但它应该可以工作。

Sum(IIf([AssessmentStatus]=3 AND [StartDate] NOT IS NULL,1,0)) AS Completed,