Extract Both Counts AND Earliest Instance from my Dataset
Using Microsoft Sql 2000
I have a requirement to be able to email a monthly report that details a number of events.
(I have got the email bit sussed).
Amongst the data I need to email is a report on the number of certain courses people have attended. (so far so easy, couple of inner joins and a Count() and Im there.)
To add to that, some of the internal courses that we run have an expiry date which prompts a referesher course. I have been able to crudely get the data I need by using the sql code for part one and sticking the result set into a temp table, then by iterating over each row in that table, getting the user Id, querying the users course attendences, sorting it on date so that the earliest is at the top, and just taking the TOP 1 record.
This seems so inefficient, so is there any way I can ammend my current query so that I can also get the date of just the earliest course that the user attended?
i.e.
SELECT uName, COUNT(uId), [ not sure what would go in here] FROM UserDetails
INNER JOIN PassDates
ON PassDates.fkUser = uId)
GROUP BY uName, uId
where, for examples sake
U开发者_如何学JAVAserDetails
uId
uName
and
PassDates
fkUser
CourseId
PassDate
Hope Ive explained this well enough for someone to help me.
To put an answer to the question..
SELECT uName, COUNT(uId), MIN(PassDate)
FROM UserDetails
INNER JOIN PassDates ON PassDates.fkUser = uId
GROUP BY uName, uId
You can turn it into a left join if you have users without any courses (yet)
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