SQL Group and Join - sql

Question

In SQL Server 2008, I have a table that looks like this:
ID | RefNum | Label | Value | Status
------------------------------------------------------
1 123 OrderNum 123456 0
2 123 TrackingNum 111111 0
3 123 ConfNum 989898 0
4 234 OrderNum 234567 1
5 234 TrackingNum 222222 1
6 234 ConfNum 878787 0
7 567 OrderNum 345678 1
8 567 TrackingNum 333333 0
9 567 ConfNum 767676 0
I want to select all records where Status = 0 and join, based on RefNum, to the 'OrderNum' and 'TrackingNum' Label values, regardless of whether 'OrderNum' and TrackingNum Statuses are 1 or 0. For example, the query should produce:
ID | RefNum | Label | Value | Status |OrderNum|TrackingNum
------------------------------------------------------------------------
1 123 OrderNum 123456 0 123456 111111
2 123 TrackingNum 111111 0 123456 111111
3 123 ConfNum 989898 0 123456 111111
6 234 ConfNum 878787 0 234567 222222
8 567 TrackingNum 333333 0 345678 333333
9 567 ConfNum 767676 0 345678 333333
Right now, my query looks like this:
SELECT Id
,mT.RefNum
,Label
,Value
,Status
,OrderNum
,TrackingNum
FROM [dbo].[myTable] AS mT
INNER JOIN (
SELECT MAX(ID) As OrderRowId, RefNum, Value AS OrderNum
FROM [dbo].[myTable]
WHERE Label= 'OrderNum'
group by RefNum, Value) AS OrderNums
ON OrderNums.RefNum= mt.RefNum
INNER JOIN (
SELECT MAX(ID) As OrderRowId, RefNum, Value AS TrackingNum
FROM [dbo].[myTable]
WHERE Label= 'TrackingNum'
group by RefNum, Value) AS TrackingNums
ON TrackingNums.RefNum= mt.RefNum
WHERE ProcessComplete = 0
This apprears to work, but requires a hash join. Would love someone to shoot holes in this or provide a more efficient solution. Thanks.

Answer 1

If there can't be duplicate order numbers or tracking numbers per reference number, you can simplify the query somewhat with a regular LEFT JOIN or JOIN;
SELECT mt.id, mt.refnum, mt.label, mt.value, mt.status,
ordno.value ordernum, trackno.value trackingnum
FROM myTable mt
LEFT JOIN myTable ordno
ON ordno.label='ordernum' and mt.refnum=ordno.refnum
LEFT JOIN myTable trackno
ON trackno.label='trackingnum' and mt.refnum=trackno.refnum
WHERE mt.status = 0;
An SQLfiddle to test with.
If there may be duplicates, you can still do a single GROUP BY to get a result;
SELECT mt.id, mt.refnum, mt.label, mt.value, mt.status,
MAX(ordno.value) ordernum, MAX(trackno.value) trackingnum
FROM myTable mt
LEFT JOIN myTable ordno
ON ordno.label='ordernum' and mt.refnum=ordno.refnum
LEFT JOIN myTable trackno
ON trackno.label='trackingnum' and mt.refnum=trackno.refnum
WHERE mt.status = 0
GROUP BY mt.id,mt.refnum,mt.label,mt.value,mt.status;
Another SQLfiddle.