Något sådant här borde göra det.
SELECT t.user, t.id, t.stuff
FROM (SELECT user, id, stuff,
ROW_NUMBER() OVER (PARTITION BY user ORDER BY id) AS RowNum
FROM YourTable) t
WHERE t.RowNum <= 5
Något sådant här borde göra det.
SELECT t.user, t.id, t.stuff
FROM (SELECT user, id, stuff,
ROW_NUMBER() OVER (PARTITION BY user ORDER BY id) AS RowNum
FROM YourTable) t
WHERE t.RowNum <= 5