Change the Value on Duplicate Rows - sql-server

Question

I need assistance on how to code duplicate Line IDs for the same Purchase Order and assign the additional line IDs with a new number. I would like to use Line ID + 100 for the additional duplicate rows. For example if Purchase Order #11 has three Line ID #5s then the first would stay as 5 and the second would be 501 and the third would be 502, however, I can only get a 1, 2 or 3 or if no duplicate just 1. I am not sure what to use to increment. I am hoping some one can assist or guide. Thank you
PurchaseOrderID LineID PackingList NewLineID
11 1 12323 1
11 1 78786 2
11 2 67523 1
11 3 44559 1
11 4 44559 1
11 5 96545 1
11 5 12323 2
11 5 34569 3
The Packing Slip causes the duplicates for the same line ID.
Below is what I am trying to use which is giving me the above NewLineID:
SELECT
PurchaseOrderID,
LineID,
PackingList,
ROW_NUMBER() over
(
partition by PurchaseOrderID, LineID
order by PurchaseOrderID, LineID
) as NewLineID
FROM PurchaseOrderTransactions

Answer 1

Using ROW_NUMBER and CASE:
WITH Cte AS(
SELECT
PurchaseOrderID,
LineID,
PackingList,
RN = ROW_NUMBER() OVER (PARTITION BY PurchaseOrderID, LineID ORDER BY LineID)
FROM PurchaseOrderTransactions
)
SELECT
PurchaseOrderID,
LineID,
PackingList,
NewLineID = CASE
WHEN RN = 1 THEN LineID
ELSE (LineID * 100) + (RN - 1)
END
FROM Cte
Without using a CTE:
SELECT
PurchaseOrderID,
LineID,
PackingList,
NewLineID =
CASE
WHEN ROW_NUMBER() OVER (PARTITION BY PurchaseOrderID, LineID ORDER BY LineID) = 1 THEN LineID
ELSE (LineID * 100) + (ROW_NUMBER() OVER (PARTITION BY PurchaseOrderID, LineID ORDER BY LineID) - 1)
END
FROM PurchaseOrderTransactions
SQL Fiddle
| PurchaseOrderID | LineID | PackingList | NewLineID |
|-----------------|--------|-------------|-----------|
| 11 | 1 | 12323 | 1 |
| 11 | 1 | 78786 | 101 |
| 11 | 2 | 67523 | 2 |
| 11 | 3 | 44559 | 3 |
| 11 | 4 | 44559 | 4 |
| 11 | 5 | 96545 | 5 |
| 11 | 5 | 12323 | 501 |
| 11 | 5 | 34569 | 502 |