If i understand your question correctly I believe this will give you the result you want:
ROW_NUMBER() OVER (PARTITION BY [SAP] ORDER BY [Timestamp] DESC) AS RN
WHERE [Parent] = :myParent
WHERE [RN] = 1
Using ROW_NUMBER in an inner query to partition by the column SAP, which based on your explanation, seems like it's L01, L02, ..., L07? Then ordering by the column Timestamp
In the outer query, we're selecting RN = 1 to get the first entry for each partition in the inner query.