How to Select the last price of parts

Question

Hi Gents,
I have below table
  TranNum | TranDate | PartNum | Price
1             | 1/1/15    | 111        | 5
2             | 1/5/15    | 212        | 7
3             | 1/7/15    | 111        | 4.5
4             | 1/8/15    | 212        | 6
5             | 1/9/15    | 212        | 5
I need to create new view to select last price per part.
  TranDate | PartNum | Price
1/7/15    | 111        | 4.5
1/9/15    | 212        | 5
Thanks in advance.
Nothing is impossible

Answer 1

Something like this will work as well...
IF OBJECT_ID('tempdb..#temp') IS NOT NULL
DROP TABLE #temp
GO
CREATE TABLE #temp (
TranNum INT PRIMARY KEY,
TranDate date,
PartNum int,
Price decimal(10,2)
CREATE UNIQUE NONCLUSTERED INDEX ix_Temp_PartNum_TranDate ON #temp (
PartNum,
TranDate
INCLUDE (
Price
WITH (DATA_COMPRESSION = PAGE)
INSERT INTO #temp (TranNum,TranDate,PartNum,Price)
VALUES
(1 ,'1/1/15 ',111,5),
(2 ,'1/5/15 ',212,7),
(3 ,'1/7/15 ',111,4.5),
(4 ,'1/8/15 ',212,6),
(5 ,'1/9/15 ',212,5)
SELECT
t1.TranNum,
t1.TranDate,
t1.PartNum,
t1.Price
FROM
#temp t1
WHERE EXISTS (
SELECT 1
FROM #temp t2
WHERE t1.PartNum = t2.PartNum
GROUP BY t2.PartNum
HAVING t1.TranDate = MAX(t2.TranDate)
Please note... Without any indexing on PartNum & TranDate, my solution will perform about the same as Martin's solution (currently the fasted of the supplied solutions).
Adding the following index, however, will show that the "EXISTS" solution can dramatically out perform the "NOT EXISTS" solution...
IF OBJECT_ID('tempdb..#temp') IS NOT NULL
DROP TABLE #temp
GO
CREATE TABLE #temp (
TranNum INT PRIMARY KEY,
TranDate date,
PartNum int,
Price decimal(10,2)
CREATE UNIQUE NONCLUSTERED INDEX ix_Temp_PartNum_TranDate ON #temp (
PartNum,
TranDate
INCLUDE (
Price
WITH (DATA_COMPRESSION = PAGE)
INSERT INTO #temp (TranNum,TranDate,PartNum,Price)
VALUES
(1 ,'1/1/15 ',111,5),
(2 ,'1/5/15 ',212,7),
(3 ,'1/7/15 ',111,4.5),
(4 ,'1/8/15 ',212,6),
(5 ,'1/9/15 ',212,5)
SELECT
t1.TranNum,
t1.TranDate,
t1.PartNum,
t1.Price
FROM
#temp t1
WHERE EXISTS (
SELECT 1
FROM #temp t2
WHERE t1.PartNum = t2.PartNum
GROUP BY t2.PartNum
HAVING t1.TranDate = MAX(t2.TranDate)
HTH,
Jason
Jason Long