将三个分组的选择查询合并为一个

Question

--ON TIME PMWO's 

SELECT LOCATION, COUNT(WONUM) AS  OnTimePMWOs
FROM
WORKORDER
WHERE   worktype = 'pm' and actfinish<=targcompdate
GROUP BY LOCATION
--PAST DUE PMWO'S

SELECT LOCATION, COUNT(WONUM) AS PastDuePMWOs
FROM
WORKORDER
WHERE  worktype = 'pm' and actfinish>=targcompdate 
GROUP BY LOCATION

--30 DayForecast- 

SELECT W.location, COUNT(W.wonum) AS Forecast30days
from
workorder AS W
INNER JOIN PMFORECAST AS P
ON W.CHANGEDATE=P.CHANGEDATE
WHERE WORKTYPE='PM' AND P.forecastdate>= GETDATE()+30
GROUP BY LOCATION

Answer 1

这是一个答案（只是基于有限问题的猜测）。我不喜欢将 CASE 语句放在聚合中，但根据环境、索引和包含表中的数据，它可能会执行得很好。发布内容时请多参与。向我们展示您的尝试，解释问题，提供数据样本，包括所需的输出，所有这些有趣的东西。问题越好，得到好答案的机会就越大。好的，马上就完成了……

DECLARE @Forecast30days DATE

SET @Forecast30days = CURRENT_TIMESTAMP + 30

SELECT
    wo.LOCATION
    ,COUNT(CASE WHEN wo.actfinish <= wo.targcompdate THEN wo.WONUM ELSE NULL END) AS OnTimePMWOs
    ,COUNT(CASE WHEN wo.actfinish >= wo.targcompdate THEN wo.WONUM ELSE NULL END) AS PastDuePMWOs
    ,COUNT(CASE WHEN pm.changedate IS NOT NULL THEN wo.WONUM ELSE NULL END) AS Forecast30days
FROM WORKORDER AS wo
LEFT JOIN PMFORECAST AS pm
    ON wo.changedate = pm.changedate
    AND pm.forecastdate >= @Forecast30days
WHERE wo.worktype = 'pm'
    AND ((wo.actfinish IS NOT NULL AND wo.targcompdate IS NOT NULL)
        OR (pm.changedate IS NOT NULL))
GROUP BY
    wo.LOCATION