Basic SQL query help needed - sql

Question

I have a table with 3 colums. Here is an example with just a few entries to demo. The table represents the dates that an item's price changes. I need a query that will tell me the prices for all the items on a specific date. The specific date may be between price changes. The price changes at midnight, so the date of the change, that is the price from then until and on the day before the previous change:
itemCode datePriceEffective price
AB 2012-01-01 9.99
AB 2012-03-02 10.50
XY 2011-09-20 34.99
I wish to get all the items prices for a given date. There is not an entry for every date, just the dates that the price changes.
so 2012-03-05 would return
AB 10.50
XY 34.99
and 2012-02-27 would return:
AB 9.99
XY 34.99
The SQL query needed to get this escapes me. Answers appreciated.
Edited as answers are going in wrong direction see italics for edit.

Answer 1

This retrieves first record by descending order of datePriceEffective per itemCode.
select top 1 with ties *
from ATable
where datePriceEffective <= #givenDate
order by row_number() over (partition by itemCode
order by datePriceEffective desc)

Answer 2

SELECT itemCode,price FRom TableNameHere WHERE datePriceEffective <= '2012-03-05'
Edit after more info - a 'simple' answer to hopefully make it easy to follow.
You're getting thelatest date for the item that is valid in your required date range and then joining the table to itself to get the price at that date
SELECT t1.itemCode,t1.price FROM
(
SELECT itemCode,MAX(datePriceEffective) AS datePriceEffective
FROM TableNameHere
WHERE datePriceEffective <= '2012-03-05'
) a
INNER JOIN TableNameHere t1 ON t1.itemCode = a.itemCode AND t1.datePriceEffective = a.datePriceEffective

Answer 3

You will need to join back to the table as follows:
declare #effdate datetime
set #effdate = CONVERT(datetime,'2012-02-27')
;WITH CTE_DATA as (
select itemCode='AB', datePriceEffective = CONVERT(Datetime,'2012-01-01'), price = 9.99
union all select itemCode='AB', datePriceEffective = CONVERT(Datetime,'2012-03-02'), price = 10.50
union all select itemCode='XY', datePriceEffective = CONVERT(Datetime,'2011-09-20'), price = 34.99
)
select
d.itemcode,
price
from
CTE_DATA d
join (
select
itemcode,
effdate = MAX(datepriceeffective)
from CTE_DATA sub where sub.datepriceeffective <= #effdate
group by itemcode
) x
on x.itemCode = d.itemCode
and x.effdate = d.datePriceEffective
Note that the CTE is just for this example, you should swap it for your real table.
UPDATE: An alternative approach is to use ROW_NUMBER and PARTITION as follows:
SELECT
itemcode,
price
FROM
(
SELECT
itemcode,
price,
rowno = ROW_NUMBER() over (partition by itemcode order by datePriceEffective desc)
from
CTE_DATA
where datePriceEffective <= #effdate
) x
where
rowno = 1
(Substitute this select for the one in the previous query to try it out on the data)

Answer 4

declare #date datetime = '2012-03-05'
select distinct itemcode,
(
select top(1) itemprice
from mytable mt2
where
mt1.itemcode = mt2.itemcode and
mt2.datepriceeffective <= #date
order by datepriceeffective desc
) as itemprice
from
mytable mt1
where
datepriceeffective <= #date

Answer 5

SELECT b.itemCode,
(SELECT Price FROM dbo.tblProducts a WHERE datePriceEffective =
(SELECT MAX(a.datePriceEffective) FROM dbo.tblProducts a WHERE a.itemCode = b.itemCode)) AS Price
FROM dbo.tblProducts b
WHERE b.datePriceEffective <= '2012-03-05'
GROUP BY b.itemCode
I have tested it! It will give you the most updated price for each Item

Answer 6

Assuming that you have another column called 'GivenDate', below is the query.
SELECT itemCode, price
FROM tblName
WHERE GivenDate= '2012-03-05'

Answer 7

This works on sql2000
SELECT s.itemCode
, ( SELECT TOP 1 price
FROM #MyTable
WHERE itemCode = s.itemCode
AND datePriceEffective < #SearchDate ) AS price
FROM (
SELECT DISTINCT itemCode
FROM #MyTable
) s