one-to-many query selecting all parents and single top child for each parent

Question

There are two SQL tables:

Parents:
+--+---------+
|id|   text  |
+--+---------+
| 1|  Blah   |
| 2|  Blah2  |
| 3|  Blah3  |
+--+---------+

Childs
+--+-----         


        

Answer 1

If you need to join different from a MAX column and any columns described in a group by closure of a nested select, you can use an APPLY function. It is a simplest solution. You also can use WITH operator. But that look harder.

SELECT p.id, p.text, CHILD_ROW.ANY_COLLUMN
FROM parent p
OUTER APPLY (SELECT TOP 1 child.ANY_COLLUMN
                  FROM child
                  WHERE child.parent = p.id
                  ORDER BY child.feature DESC 
                  ) CHILD_ROW