Question

EDIT: I’m using SQL Server

I looked around for an example of this but couldn’t find anything so I’ll start a new thread…

I have 3 tables.

Account

• AccountID
• FirstName
• LastName

AccountEnroll

• AccountEnrollID
• AccountID
• AccountTypeID
• EnrollDate

AccountType

• AccountTypeID
• AccountType

The AccountEnroll table is a bridge table to track each customer’s enrollment history. I want to use the “EnrollDate” column to determine the current account type for each customer. I need to write a SELECT statement that can display AccountID, FirstName, LastName, (current)AccountType.

I am having trouble getting my resultset to display only the MAX(EnrollDate) record for each customer.

Answer 1

You can use common table expressions to do this pretty simply.

with cte as (

select A.FirstName, A.LastName, AT.AccountType, AE.EnrollDate, row_number() over (partition by AE.AccountID order by EnrollDate desc) as [rn]
from Account as A
inner join AccountEnrolled as AE
   on A.AccountId = AE.AccountId
inner join AccountType as AT
   on AE.AccountTypeId = AT.AccountTypeId

)
select FirstName, LastName, AccountType, EnrollDate
from cte
where rn = 1