Question

I want to do a similiar thing like this guy:
T-SQL Subquery Max(Date) and Joins

I have to do this with an n:m relation.

So the layout is:

tbl_Opportunity
tbl_Opportunity_tbl_OpportunityData
tbl_OpportunityData

So as you see there is an intersection table which connects opportunity with opportunitydata.
For every opportunity there are multiple opportunity datas. In my view i only want a list with all opportunites and the data from the latest opportunity datas.

I tried something like this:

SELECT     
    dbo.tbl_Opportunity.Id, dbo.tbl_Opportunity.Subject, 
    dbo.tbl_User.UserName AS Responsible, dbo.tbl_Contact.Name AS Customer, 
    dbo.tbl_Opportunity.CreationDate, dbo.tbl_Opportunity.ActionDate AS [Planned Closure], 
    dbo.tbl_OpportunityData.Volume, 
    dbo.tbl_OpportunityData.ChangeDate, dbo.tbl_OpportunityData.Chance
FROM         
    dbo.tbl_Opportunity 
INNER JOIN
    dbo.tbl_User ON dbo.tbl_Opportunity.Creator = dbo.tbl_User.Id 
INNER JOIN
    dbo.tbl_Contact ON dbo.tbl_Opportunity.Customer = dbo.tbl_Contact.Id 
INNER JOIN
    dbo.tbl_Opprtnty_tbl_OpprtnityData ON dbo.tbl_Opportunity.Id = dbo.tbl_Opprtnty_tbl_OpprtnityData.Id 
INNER JOIN
    dbo.tbl_OpportunityData ON dbo.tbl_Opprtnty_tbl_OpprtnityData.Id2 = dbo.tbl_OpportunityData.Id

The problem is my view now includes a row for every opportunity data, since I don’t know how to filter that I only want the latest data.

Can you help me? is my problem description clear enough?

thank you in advance 🙂
best wishes,
laurin

Answer 1

; WITH Base AS (
    SELECT     dbo.tbl_Opportunity.Id, dbo.tbl_Opportunity.Subject, dbo.tbl_User.UserName AS Responsible, dbo.tbl_Contact.Name AS Customer, 
                      dbo.tbl_Opportunity.CreationDate, dbo.tbl_Opportunity.ActionDate AS [Planned Closure], dbo.tbl_OpportunityData.Volume, 
                      dbo.tbl_OpportunityData.ChangeDate, dbo.tbl_OpportunityData.Chance
    FROM         dbo.tbl_Opportunity INNER JOIN
                      dbo.tbl_User ON dbo.tbl_Opportunity.Creator = dbo.tbl_User.Id INNER JOIN
                      dbo.tbl_Contact ON dbo.tbl_Opportunity.Customer = dbo.tbl_Contact.Id INNER JOIN
                      dbo.tbl_Opprtnty_tbl_OpprtnityData ON dbo.tbl_Opportunity.Id = dbo.tbl_Opprtnty_tbl_OpprtnityData.Id INNER JOIN
                      dbo.tbl_OpportunityData ON dbo.tbl_Opprtnty_tbl_OpprtnityData.Id2 = dbo.tbl_OpportunityData.Id    
)

, OrderedByDate AS (
    SELECT *, ROW_NUMBER() OVER (PARTITION BY Id ORDER BY ChangeDate DESC) RN FROM Base
)

SELECT * FROM OrderedByDate WHERE RN = 1

To make it more readable I’m using CTE (the WITH part). In the end the real “trick” is doing a ROW_NUMBER() partitioning the data by tbl_Opportunity.Id and ordering the partitions by ChangeDate DESC (and I call it RN). Clearly the maximum date in each partition will be RN = 1 and then we filter it by RN.

Without using CTE it will be something like this:

SELECT * FROM (
    SELECT     dbo.tbl_Opportunity.Id, dbo.tbl_Opportunity.Subject, dbo.tbl_User.UserName AS Responsible, dbo.tbl_Contact.Name AS Customer, 
                      dbo.tbl_Opportunity.CreationDate, dbo.tbl_Opportunity.ActionDate AS [Planned Closure], dbo.tbl_OpportunityData.Volume, 
                      dbo.tbl_OpportunityData.ChangeDate, dbo.tbl_OpportunityData.Chance,
                      ROW_NUMBER() OVER (PARTITION BY dbo.tbl_Opportunity.Id ORDER BY dbo.tbl_OpportunityData.ChangeDate DESC) RN
    FROM         dbo.tbl_Opportunity INNER JOIN
                      dbo.tbl_User ON dbo.tbl_Opportunity.Creator = dbo.tbl_User.Id INNER JOIN
                      dbo.tbl_Contact ON dbo.tbl_Opportunity.Customer = dbo.tbl_Contact.Id INNER JOIN
                      dbo.tbl_Opprtnty_tbl_OpprtnityData ON dbo.tbl_Opportunity.Id = dbo.tbl_Opprtnty_tbl_OpprtnityData.Id INNER JOIN
                      dbo.tbl_OpportunityData ON dbo.tbl_Opprtnty_tbl_OpprtnityData.Id2 = dbo.tbl_OpportunityData.Id    
) AS Base WHERE RN = 1