Query table with all names in one statement - sql

Question

I have a table that I cannot alter and I am trying to wrap my head around an appropriate way to query this table in one statement based on one given value.
Roughly here's what the table looks like:
What I'm after is a way to query the table using only the SubBody code in order to get all names associated with it.
for example,
<query> where SubBody = '1001'
returns
| HName | HSName | BName | BSName |
+-----------------------------------+
| Toys | Sport | Ball | Baseball |

Answer 1

SELECT Head.Name as HName ,
SubHead.Name as HSName ,
Body.Name as BName ,
SubBody.Name as BSName
FROM yourTable as SubBody
JOIN yourTable as Body
ON SubBody.Body = Body.Body
AND Body.SubBody IS NULL
JOIN yourTable as SubHead
ON Body.SubHead = SubHead.SubHead
AND SubHead.Body IS NULL
JOIN yourTable as Head
ON SubHead.Head = Head.Head
AND Head.SubHead IS NULL
WHERE SubBody.SubBody = '1001'

Answer 2

Although you can express the logic as joins, for some reason correlated subqueries come to mind first:
select (select th.name from t th where th.head = t.head and th.subhead is null) as hname,
(select ts.name from t ts where ts.head = t.head and ts.subhead = t.subhead and t.body is null) as sname,
(select tb.name from t tb where tb.head = t.head and tb.subhead = t.subhead and tb.body = t.body and tb.subbody is null) as bname,
t.name as bsname
from t
where t.subbody = 1001

Answer 3

This answer is close to what Juan Carlos has posted. Which one you like depends a bit on your style.
WITH BaseRecord AS(
SELECT *
FROM ToyTable
WHERE SubBody = '1001'
)
SELECT
h.Name AS HName,
hs.Name AS HSName,
b.Name AS BName,
bs.Name AS BSName
FROM BaseRecord bs
INNER JOIN ToyTable b ON bs.Body = b.Body AND ISNULL(b.SubBody,'') = ''
INNER JOIN ToyTable hs ON bs.SubHead = hs.SubHead AND ISNULL(hs.Body,'') = ''
INNER JOIN ToyTable h ON bs.Head = h.Head AND ISNULL(h.SubHead,'') = ''
I'm not sure whether your "empty" cells contain nulls or empty strings. Either way, both are taken into account here.