how to display only aggregate or flagged results in a Case statement

问题

I have a query that gets break time exceptions. I use Case statements to flag the records. The problem is, I only want to list those that are flagged or have a "1" in the Skipped break, or "ShortBreak" column?

SELECT        lEmployeeID, sFirstName, sLastName, SUM(TotalHours) AS TotalHours, DATEDIFF(mi, MIN(dtTimeOut), MAX(dtTimeIn)) AS BreakTime, 
                         CASE WHEN SUM(ftc.TotalHours) > 6 AND DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) < 0 THEN 1 ELSE 0 END AS SkippedBreak, CASE WHEN DATEDIFF(mi, 
                         MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) < 30 AND DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) > 0 THEN 1 ELSE 0 END AS ShortBreak
FROM            dbo.fTimeCard(@StartDate, @EndDate, @DeptList, @iActive, @EmployeeList) AS ftc
WHERE        (DID IS NOT NULL) OR
                         (DID IS NOT NULL) AND (dtTimeOut IS NULL)
GROUP BY lEmployeeID, sFirstName, sLastName, TotalHours

回答1:

You cannot filter in the WHERE part of the query you've got, because the grouping is not yet performed at that point. You can use a HAVING clause to do additional filtering after grouping:

SELECT        lEmployeeID, sFirstName, sLastName, SUM(TotalHours) AS TotalHours, DATEDIFF(mi, MIN(dtTimeOut), MAX(dtTimeIn)) AS BreakTime, 
                     CASE WHEN SUM(ftc.TotalHours) > 6 AND DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) < 0 THEN 1 ELSE 0 END AS SkippedBreak, CASE WHEN DATEDIFF(mi, 
                     MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) < 30 AND DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) > 0 THEN 1 ELSE 0 END AS ShortBreak
FROM            dbo.fTimeCard(@StartDate, @EndDate, @DeptList, @iActive, @EmployeeList) AS ftc
WHERE        (DID IS NOT NULL) OR
                     (DID IS NOT NULL) AND (dtTimeOut IS NULL)
GROUP BY lEmployeeID, sFirstName, sLastName, TotalHours
HAVING SUM(ftc.TotalHours) > 6 AND DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) < 0
OR DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) < 30 AND DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) > 0

Or you can use a subquery, and filter the results of the subquery:

SELECT *
FROM (
SELECT        lEmployeeID, sFirstName, sLastName, SUM(TotalHours) AS TotalHours, DATEDIFF(mi, MIN(dtTimeOut), MAX(dtTimeIn)) AS BreakTime, 
                     CASE WHEN SUM(ftc.TotalHours) > 6 AND DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) < 0 THEN 1 ELSE 0 END AS SkippedBreak, CASE WHEN DATEDIFF(mi, 
                     MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) < 30 AND DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) > 0 THEN 1 ELSE 0 END AS ShortBreak
FROM            dbo.fTimeCard(@StartDate, @EndDate, @DeptList, @iActive, @EmployeeList) AS ftc
WHERE        (DID IS NOT NULL) OR
                     (DID IS NOT NULL) AND (dtTimeOut IS NULL)
GROUP BY lEmployeeID, sFirstName, sLastName, TotalHours
) AS sub
WHERE sub.SkippedBreak = 1 OR sub.ShortBreak = 1

回答2:

You need to add HAVING

...
HAVING ((
    SUM(ftc.TotalHours) > 6
    AND DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) < 0
) OR (
    DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) < 30
    AND DATEDIFF(mi, MIN(ftc.dtTimeOut), MAX(ftc.dtTimeIn)) > 0
))

来源：https://stackoverflow.com/questions/20721824/how-to-display-only-aggregate-or-flagged-results-in-a-case-statement

标签

sql

sql-server

tsql

sql-server-2005