How to select most recent record while using self join in SQL Server 2014 - sql-server-2014

Question

+-----------+-------------+-------------+----------+
| Item Code | Vendor Code | Direct Cost | Date |
+-----------+-------------+-------------+----------+
| 6994 | 1441 | 3.86 | 20150512 |
| 6994 | 1441 | 3.86 | 20150910 |
| 6994 | 1441 | 4.62 | 20160425 |
| 6994 | 1441 | 4.62 | 20161017 |
| 6994 | 1441 | 4.05 | 20170330 |
| 6994 | 1441 | 4.10 | 20170624 |
+-----------+-------------+-------------+----------+
I am creating a view and I have joined 2 tables PO Header and PO Details, so in this example above I just need 1 line result because Item Code and Vendor Code is repeating, I have achieved this by using the self join on the table but the main requirement is to pick 1 line with most recent date record i.e. 20170624 and Direct Cost is = 4.10
Please see my code below.
l.AUDTDATE is the date column but not in the date format, so I have converted it into date format and in descending order but I am struggling in getting the 1 line with the most recent date.
Thanks
SELECT TOP (100) PERCENT
dbo.NavMdItem.nav_item_code,
dbo.NavMdVendor.nav_vendor_code,
l.ORDERUNIT AS uom,
'' AS variant_code,
h.POCURR AS currency_code,
'1' AS minimum_qty,
l.UNITCOST AS direct_unit_cost,
SUBSTRING(CAST(h.DAYENDDATE AS VARCHAR(50)), 7, 2) + '/' +
SUBSTRING(CAST(h.DAYENDDATE AS VARCHAR(50)), 5, 2) + '/' +
SUBSTRING(CAST(h.DAYENDDATE AS VARCHAR(50)), 0, 5) AS starting_date,
l.DAYENDSEQ,
CONVERT(DATETIME, CAST(l.AUDTDATE AS VARCHAR(50)), 106) AS date
FROM
skh.POPORAH AS h
INNER JOIN
skh.POPORAL AS l ON h.PORAHSEQ = l.PORAHSEQ AND h.DAYENDSEQ = l.DAYENDSEQ
INNER JOIN
dbo.NavMdItem ON l.ITEMNO = dbo.NavMdItem.item_long_code COLLATE Latin1_General_CI_AS
INNER JOIN
dbo.NavMdVendor ON h.VENDOR = dbo.NavMdVendor.vendor_short_code COLLATE Latin1_General_CI_AS
WHERE
(NOT (l.ITEMNO LIKE 'MISC'))
AND (l.ITEMEXISTS = 1)
AND (dbo.NavMdVendor.entity_code = 10)
AND (h.DAYENDDATE > 20150101)
AND (dbo.NavMdItem.nav_item_code = 6499)
AND ((SELECT COUNT(*) AS Expr1
FROM skh.POPORAL AS f
WHERE (DAYENDSEQ = l.DAYENDSEQ)
AND (DAYENDSEQ <= l.DAYENDSEQ)) < 2)
ORDER BY
l.AUDTDATE DESC

Answer 1

You want to group by item code and vendor code and select MAX date.
Is there zero chance of having two on the same date?
UPDATE:
Here is some code that will do what you're wanting. Notice I assumed valid datetime data in the [aud_date] column.
CREATE TABLE #Stuff(
item_code int
,vendor_code int
,direct_cost money
,aud_date datetime
)
INSERT #Stuff VALUES (6994,1441,3.86,'2015-05-12 11:32:12')
INSERT #Stuff VALUES (6994,1441,3.86,'2015-09-10 05:11:00')
INSERT #Stuff VALUES (6994,1441,4.62,'2016-04-25 19:43:43')
INSERT #Stuff VALUES (6994,1441,4.62,'2016-10-17 11:12:13')
INSERT #Stuff VALUES (6994,1441,4.05,'2017-03-30 01:02:03')
INSERT #Stuff VALUES (6994,1441,4.10,'2017-06-24 12:12:12')
SELECT
*
FROM
#Stuff
WHERE
aud_date = (
SELECT MAX(aud_date)
FROM
#Stuff
WHERE
item_code = item_code
AND
vendor_code = vendor_code
GROUP BY
item_code, vendor_code
)
DROP TABLE #Stuff