We Shall See

My goal is to select the amendment id of the most recently amended gift.

The most recently amended gift will have the highest sequence number.

giftamendment table

sql over clause

https://msdn.microsoft.com/en-us/library/ms189461.aspx

In laymans terms, the over clause makes the row I want have a value of 1 for
the uno field.

select 
  giftid, 
  sequence, 
  amendmentid,
  row_number()
  over(partition by giftid order by sequence desc) uno 
from giftamendment

query results

Final Solution

Finally I just select the rows from summary where uno is 1.

with summary as (
  select 
    giftid, 
    sequence, 
    amendmentid,
    row_number()
    over(partition by giftid order by sequence desc) uno 
  from giftamendment
)
select amendmentid from summary where uno = 1

query results