在 sql 中按问题分组

Question

我正在尝试将 08:00 和 18:00 之间的会话添加到新列中。你可以在 CTE 中看到我的最后一个案例。对于每个日期，都应该有一个新列 "TotalRestrictedSessions"，它表示在该特定日期有多少会话。如果有none，在这种情况下我必须写0。我怀疑我的问题是我转换日期时？

WITH ParkeonCTE
AS
(
SELECT 
    OccDate = CONVERT(DATE, OC.LocalStartTime),
    TotalOccSessions = COUNT(OC.SessionId),
    AuthorityId,
    TotalOccDuration = ISNULL(SUM(OC.DurationMinutes),0),
    TotalNumberOfOverstay = SUM(CAST(OC.IsOverstay AS INT)),
    TotalMinOfOverstays = ISNULL(SUM(OC.OverStayDurationMinutes),0),
    (CASE
        WHEN OC.OspId IS NULL THEN 'OffStreet' ELSE 'OnStreet'
        END
    ) AS ParkingContextType,
    (CASE
        WHEN CAST(OC.LocalStartTime AS TIME) >= '08:00:00' AND CAST(OC.LocalStartTime AS TIME) <= 
 '18:00:00'
            THEN COUNT(OC.SessionId)
     END
    ) AS TotalRestrictedSessions
FROM Analytics.OccupancySessions AS OC
WHERE OC.AuthorityId IS NOT NULL
GROUP BY  CONVERT(DATE,OC.LocalStartTime), OC.AuthorityId,OC.OspId
)
SELECT OC.OccDate,
   OC.ParkingContextType,
   OC.AuthorityId,
   OC.TotalRestrictedSessions,
   SUM(OC.TotalOccSessions) AS TotalOccSessions,
   AVG(OC.TotalOccDuration) AS AvgOccMinutesDuration, -- wrong
   SUM(OC.TotalOccDuration) AS TotalOccDuration,
   SUM(OC.TotalNumberOfOverstay) AS TotalNumberOfOverstay,
   SUM(OC.TotalMinOfOverstays) AS TotalMinOfOverstays,
   CAST(AVG(OC.TotalMinOfOverstays) AS decimal(10,2)) AS AvgMinOfOverstays -- wrong
  FROM ParkeonCTE AS OC
GROUP BY OC.OccDate, OC.AuthorityId, OC.ParkingContextType
ORDER BY OC.OccDate DESC

Answer 1

您只需将聚合移到 CASE 表达式之外，称为条件聚合。

  SUM(CASE
        WHEN CAST(OC.LocalStartTime AS TIME) >= '08:00:00' 
        AND CAST(OC.LocalStartTime AS TIME) <= '18:00:00'
         THEN 1
         ELSE 0
      END
    ) AS TotalRestrictedSessions

一般来说，您应该在问题中包含当前的查询结果和您想要的结果，以便更容易找出问题所在。

在 sql 中按问题分组

group by issue in sql

sql

tsql

group-by

common-table-expression