COUNT (Distinct Column) = 0 with GROUP BY

Question

COUNT (Distinct Column) = 0 with GROUP BY

apr301975

SSC Journeyman

Points: 82
More actions
March 19, 2008 at 11:36 pm

#185452

I have a table of users and date when they logged on to a system. I am trying to count how many distinct users logged on for each day of the week. The SQL below works when there's at least a user for each day. But when there is no user for a particular day such as Sunday, I still want it to return "SUN 0 "
I learned that you can use GROUP BY ALL and it works but the "ALL" is deprecated beyond SQL 2005.
------------------------------------
SELECT UPPER(LEFT(DATENAME(dw, StartTime), 3)) AS DayOfWeek,
COUNT(DISTINCT UserID) AS NumberOfUser
FROM testUserLoginDuration
WHERE Archived = 0
GROUP BY UPPER(LEFT(DATENAME(dw, StartTime), 3))
ORDER BY
CASE WHEN UPPER(LEFT(DATENAME(dw, StartTime), 3)) = 'MON' THEN 1
WHEN UPPER(LEFT(DATENAME(dw, StartTime), 3)) = 'TUE' THEN 2
WHEN UPPER(LEFT(DATENAME(dw, StartTime), 3)) = 'WED' THEN 3
WHEN UPPER(LEFT(DATENAME(dw, StartTime), 3)) = 'THU' THEN 4
WHEN UPPER(LEFT(DATENAME(dw, StartTime), 3)) = 'FRI' THEN 5
WHEN UPPER(LEFT(DATENAME(dw, StartTime), 3)) = 'SAT' THEN 6
WHEN UPPER(LEFT(DATENAME(dw, StartTime), 3)) = 'SUN' THEN 7
END
--------------
returns
MON 6
TUE 3
WED 5
THU 3
FRI 2
SAT 1

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Gail Shaw SSC Guru Points: 1004514 More actions · Answer 1

Please don't cross post. It wastes people's time and scatters replies. Many of the regular readeers read all the forumns.

Please direct any replies to the following thread.

http://www.sqlservercentral.com/Forums/Topic472063-338-1.aspx

Thanks

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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