How to generate a date to be included in UNPIVOT results without a loop? - tsql

Question

Say I had an example like so, where Im transposing columns into rows with UNPIVOT.
DECLARE #pvt AS TABLE (VendorID int, Emp1 int, Emp2 int, Emp3 int, Emp4 int, Emp5 int);
INSERT INTO #pvt (VendorId,Emp1,Emp2,Emp3,Emp4,Emp5) VALUES (1,4,3,5,4,4);
INSERT INTO #pvt (VendorId,Emp1,Emp2,Emp3,Emp4,Emp5) VALUES (2,4,1,5,5,5);
INSERT INTO #pvt (VendorId,Emp1,Emp2,Emp3,Emp4,Emp5) VALUES (3,4,3,5,4,4);
INSERT INTO #pvt (VendorId,Emp1,Emp2,Emp3,Emp4,Emp5) VALUES (4,4,2,5,5,4);
INSERT INTO #pvt (VendorId,Emp1,Emp2,Emp3,Emp4,Emp5) VALUES (5,5,1,5,5,5);
--Unpivot the table.
SELECT VendorID, Employee, Orders
FROM
(SELECT VendorID, Emp1, Emp2, Emp3, Emp4, Emp5
FROM #pvt) p
UNPIVOT
(Orders FOR Employee IN
(Emp1, Emp2, Emp3, Emp4, Emp5)
)AS unpvt;
GO
Which produces results like this
VendorID Employee Orders
1 Emp1 4
1 Emp2 3
1 Emp3 5
1 Emp4 4
1 Emp5 4
2 Emp1 4
2 Emp2 1
2 Emp3 5
2 Emp4 5
2 Emp5 5
3 Emp1 4
3 Emp2 3
3 Emp3 5
3 Emp4 4
3 Emp5 4
However, I want to include an "incremental date like so that it repeats in a group for each Vendor and the results would be like this
VendorID Employee Orders OrderDate
1 Emp1 4 01/01/2014
1 Emp2 3 02/01/2014
1 Emp3 5 03/01/2014
1 Emp4 4 04/01/2014
1 Emp5 4 05/01/2014
2 Emp1 4 ..
2 Emp2 1
2 Emp3 5
2 Emp4 5
2 Emp5 5
3 Emp1 4
3 Emp2 3
3 Emp3 5
3 Emp4 4
3 Emp5 4
The kicker is that I want to try to do this without resorting to a loop since the transposed results are going to be about 100K records. Is there a way to generate that date field like that without looping over the results?
[edit]
I think, but not sure yet, that [this]1 post might help, using ROW NUMBER

Answer 1

You can use:
Dateadd(DAY, row_number() over( partition by VendorId Order by Employee), #stardate)
According to your example you can partition by vendorId and order by Employee. But you can change just like a regular order by.