SQL Server Data Query on Possible Rows - sql

Question

SQL Server 2000
I have a table which lists out the months where a particular product can be sold.
ProductCode MonthNum MonthName
XXX 1 January
XXX 2 February
YYY 1 January
YYY 3 March
YYY 5 May
ZZZ 6 June
ZZZ 7 July
I need to construct a query that would allow me to pass some parameters:
ProductCode
LatestMonthNum
LatestYear
FutureForecast
that would allow me to construct a set of data list with the total rows based on the number of FutureForecast value and the rows' value would be beyond the passed LatestMonthNum and LatestYear parameter values.
For example, if I pass the following values to the query:
ProductCode YYY
LatestMonthNum 5
LatestYear 2012
FutureForecast 5
I would have the data as follows:
ProductCode MonthNum Year
YYY 1 2013
YYY 3 2013
YYY 5 2013
YYY 1 2014
YYY 3 2014

Answer 1

I would create a table of months and years in the future (something like a numbers table):
CREATE TABLE future (month int, year int);
DECLARE #m int;
SET #m = 1;
DECLARE #y int;
SET #y = 2000;
WHILE (#y < 2200) -- will my brain be in a jar by now?
BEGIN
WHILE (#m < 13)
BEGIN
INSERT INTO future (month, year) VALUES (#m, #y);
SET #m += 1;
END
SET #m = 1;
SET #y += 1;
END;
Then you can join your products table with the future!
SELECT TOP #FutureForecast
p.ProductCode, p.MonthNum, f.[year]
FROM Products AS p
JOIN future AS f ON f.[month] = p.MonthNum
WHERE
p.ProductCode = #ProductCode
AND (p.MonthNum > #LatestMonthNum OR f.[year] > #LatestYear)
ORDER BY f.[year], p.MonthNum

Answer 2

Like this?
Select * From
(SELECT ProductCode, MonthNum, Year, RANK() OVER
(PARTITION BY ProductCode ORDER BY
CAST('1/' + CAST(MonthNum AS varchar) + '/' + CAST(Year AS varchar)
AS datetime)) AS 'RANK'
FROM dbo.MyTable
WHERE (ProductCode = #productcode) AND (MonthNum > #monthnum) AND
(Year > #latestyear)) tbl Where tbl.Rank <= #futureforcast
Where is your year column?

Answer 3

I believe this should work. You could turn the loop into a CTE (only for SQL 2005+), but I am not sure if that gains you that much in this case.
CREATE TABLE #TempOrder
(Order INT IDENTITY (1,1), ProductCode VARCHAR(MAX), MonthNum INT)
INSERT INTO #TempOrder
SELECT ProductCode, MonthNum
FROM ProductTable
WHERE ProductCode = #ProductCode AND MonthNum > #LatestMonthNum
ORDER BY MonthNum DESC
--Increment the year from the start if it is already over the max stored
IF NOT EXISTS (SELECT 1 FROM #TempOrder)
SET #LatestYear = #LatestYear + 1
INSERT INTO #TempOrder
SELECT ProductCode, MonthNum
FROM ProductTable
WHERE ProductCode = #ProductCode AND MonthNum <= #LatestMonthNum
ORDER BY MonthNum DESC
DECLARE #MaxId
SELECT #MaxId = MAX(Id) FROM #TempOrder
CREATE TABLE #ForecastData (ProductCode VARCHAR(MAX), MonthNum INT, Year INT)
DECLARE #CurrentId INT
SET #CurrentId = 1
DECLARE #CurrentCount INT
SET #CurrentCount = 0
WHILE(#CurrentCount < #FutureForeCast)
BEGIN
INSERT INTO #ForecastData
SELECT ProductCode, MonthNum, #LatestYear
FROM #TempOrder
WHERE Id = #CurrentId
--Increment the Id, and if it's over the max in the table
--Reset to 1 and increment for a new year
SET #CurrentId = #CurrentId + 1
IF #CurrentId > #MaxId
BEGIN
SET #CurrentId = 1
SET #LatestYear = #LatestYear + 1
END
SET #CurrentCount = #CurrentCount + 1
END
SELECT #ForecastData
(This solution only for SQL 2005+)I am extremely rusty on CTE's but I figured I would give my attempt at this as a CTE also. This replaces everything from above from CREATE TABLE #ForecastData.... down:
;
WITH ForecastData (ProductCode, MonthNum, Year)
AS
(
-- Anchor member definition
SELECT ProductCode, MonthNum, #LatestYear AS Year, Id AS LastId
FROM #TempOrder
WHERE Id = 1
UNION ALL
-- Recursive member definition
SELECT ProductCode, MonthNum,
CASE WHEN Id = 1 THEN Year + 1 ELSE Year,
Id AS LastId
FROM #TempOrder
JOIN ForecastData
ON Id = CASE
WHEN LastId = #MaxId THEN 1
ELSE LastId + 1
END
)
-- Statement that executes the CTE
SELECT *
FROM ForecastData;
GO