问题
I use MS SQL Server 2016 and try to query the MS Dynamics 2016 on-premise DB efficiently. You don't need special knowledge about Dynamics to answer my problem because it's rather an SQL but a CRM problem.
Suppose you have entities FilteredAccounts and FilteredActivities (that's the name in Dynamics View)
FilteredActivites have the following columns:
accountid
name
FilteredActivites have the following columns:
activityid
actualend [DATETIME]
regardingobjectid (referring to account)
statecode (int meaning 1 = completed)
What I am trying to achieve is a list of all Accounts which shows to each account the most recent completed activity.
I tried to get the most recent activities by:
SELECT TOP 1 *
FROM [dbo].[FilteredActivityPointer] As Activities
ORDER BY Activities.actualend DESC
Now how do I join FilteredAccounts and FilteredActivities efficiently so that per FilteredAccount row I just get the most recent FilteredActivity? Is the way I compute the most recent actitivity an efficient way of doing this`(i.e. > 1.000.000 rows for activities stored in the DB). Is there a better way of doing this (like triggering the script which stores the id of the most recent activityid on the account whenever an activity is added / changed. Would this harm the integrity of the CRM system? You don't want to change the system db of your crm this way I suppose?
回答1:
With the right indexes, cross apply
might be the fastest approach:
select fa.*
from filteredaccounts fac cross apply
(select top (1) fa.*
from FilteredActivites fa
where fa.regardingobjectid = fac.accountid and fa.statecode = 1
order by fa.actualend desc
) fa;
The index you want is on FilteredActivites(regardingobjectid, accountid, actualend)
.
来源:https://stackoverflow.com/questions/61803298/sql-query-get-most-recent-activiy-per-account-efficient-query