SQL Server 2008: Help in optimizing a query using a cursor - sql

Question

I need to rewrite this so it does not cause an overrun on my db. I need to rewrite it so it does not use a cursor.
Thank you.

Answer 1

UPDATED Here's some test data:
CREATE TABLE #TableB(SKU INT, BeginYear INT, EndYear INT, OptionA VARCHAR(10), OptionB VARCHAR(10))
INSERT INTO #TableB(SKU, BeginYear, EndYear, OptionA, OptionB)
VALUES (1, 1920, 1950, 'option1', 'option1'),
(1, 1980, 2001, 'option1', 'option2'),
(1, 1940, 1952, 'option1', 'option1'), --overlapping years
(2, 2001, 2005, 'option1', 'option1')
CREATE TABLE #TableA(SKU INT, OptionA VARCHAR(10), OptionB VARCHAR(10), Years INT)
Then you can try a recursive CTE:
;WITH CTE AS
(
SELECT DISTINCT SKU, BeginYear, EndYear, OptionA, OptionB
FROM #TableB
UNION ALL
SELECT SKU, BeginYear+1, EndYear, OptionA, OptionB
FROM CTE
WHERE BeginYear < EndYear
)
INSERT INTO #TableA(SKU, OptionA, OptionB, Years)
SELECT DISTINCT SKU, OptionA, OptionB, BeginYear
FROM CTE
OPTION(MAXRECURSION 0)
SELECT *
FROM #TableA
ORDER BY SKU, OptionA, OptionB, Years
Here there's no cartesian product.

Answer 2

You can easily substitute a while loop for a cursor and if you are blowing out your tempdb then do some intermediate transactions
declare #counter int
declare #temptable as tatble (RecID int Identity(1,1),
SKU Varchar(25),
OptionA Varchar(50),
OptionB Varchar(50),
CurrentYear Int,
EndYear Int)
insert into #temptable
Select SKU,OptionA, OptionB, BeginYear,EndYear
From TableB
set #counter = (select max(recid) from #temptable)
begin transaction
while #counter <> 0
Begin
(***whatever sql logic***)
if (#counter % 5000 = 0) and ##error = 0
commit Transaction
begin Transaction
set #counter = #counter -1
End
commit transaction

Answer 3

May be use less number of times the insert happen
Declare #temp table (
SKU Varchar(25),
OptionA Varchar(50),
OptionB Varchar(50),
[Year] Int
)
While ##FETCH_STATUS = 0
Begin
While #CurrentYear <= #EndYear
Begin
Insert Into #temp(SKU, OptionA, OptionB, Years)
Values(#SKU, #OptionA, #OptionB, #CurrentYear)
Set #CurrentYear = #CurrentYear + 1
End
Insert Into TableA
Select * From #temp
Delete From #temp
Fetch Next From #Row Into #SKU, #CurrentYear, #EndYear, #OptionA, #OptionB
End