Microsoft Access 2010: Select most recent max Record ID for each LANID

Question

I need to filter out this data based on some criteria.

1. For every unique LANID, a user can have up to 2 records. Some users will only have 1 record.
2. I need to select the max Record ID for each LANID.

Answer 1

因此，创建一个查询以确定按LANID分组时的max(recordID) ，然后使用第二个查询作为第一个查询作为数据源，将其连接回到基于LANID和max(recordID)

Answer 2

Assuming the last update date is not duplicated for a given row, then one method is to use a correlated subquery to get the last date and then get the rest of the columns in the row:

select sd.*
from sampleData as sd
where sd.RecordId = (select max(sd2.RecordId)
                     from sampleData as sd2
                     where sd2.lanId = sd.lanId
                    );

EDIT:

If you wanted the largest record id for the most recent update date:

select sd.*
from sampleData as sd
where sd.RecordId = (select top 1 sd2.RecordId
                     from sampleData as sd2
                     where sd2.lanId = sd.lanId
                     order by sd2.lastUpdateDate desc, sd2.RecordId desc
                    );