Cursor inside cursor: Alternative? - sql-server

Question

So, I have the following problem:
I have 4 tables: Range Information, Range Percentage, DGRange and SGRange
Range information has a 1 - N to Range Percentage ( IE: N percentages to 1 range )
Both DGRange and SGRange connect these two tables to other external fonts.
It shouldn't be that way. But that is the way the system was built, and now I can only fix the problems that appear on that stupid decision.
In any case, we found times that both DGRange and SGRange are pointed to the same primary key when they shouldnt - and as such, once the system changes any information from that range it screws up something else in the system. As such, I must find out every time we have this duplicates ( very easy to do ) and duplicate the whole record on RangeInformation/RangePercentage and point one of them to the new record.
My problem is that right now I am thinking of using a cursor inside a cursor, and I believe that there may be a easier way to do it.
Is there a better way?
DECLARE #range nvarchar(10)
DECLARE #rangeinfoid nvarchar(10)
DECLARE #lowerlimit money
DECLARE #Upperlimit money
DECLARE #CurrentYear smallint
DECLARE #Percentage float
DECLARE subgroup_cursor CURSOR FOR
SELECT distinct a.RangeInformationId
FROM SubgroupRange a, DiscountGroupRange b
where a.RangeInformationId = b.RangeInformationId
DECLARE rangeperc_cursor CURSOR FOR
SELECT CurrentYear,
Percentage
from RangePercentage
where RangeInformationId = #range
OPEN subgroup_cursor
FETCH NEXT FROM subgroup_cursor INTO #range
WHILE ##FETCH_STATUS = 0
BEGIN
select #rangeinfoid = RangeInformationId ,
#lowerlimit = LowerLimit,
#Upperlimit = UpperLimit
from RangeInformation
where RangeInformationId = #range
--Add insert here
OPEN rangeperc_cursor
FETCH NEXT FROM subgroup_cursor INTO #CurrentYear, #Percentage
WHILE ##FETCH_STATUS = 0
BEGIN
print(#CurrentYear)
print(#Percentage)
--Add insert here
FETCH NEXT FROM rangeperc_cursor INTO #CurrentYear, #Percentage
END
FETCH NEXT FROM subgroup_cursor INTO #range
END
CLOSE subgroup_cursor
DEALLOCATE subgroup_cursor
CLOSE rangeperc_cursor
DEALLOCATE rangeperc_cursor

Answer 1

As I commented above this is difficult to know exactly what you are trying to do but does something like this get you the data you need?
select ri.RangeInformationId
, ri.LowerLimit
, ri.UpperLimit
from RangeInformation ri
join SubgroupRange sr on sr.RangeInformationId = ri.RangeInformationId
join DiscountGroupRange dgr on dgr.RangeInformationId = sr.RangeInformationId
You really should get on the habit of this style of join. It is a little cleaner code wise and helps prevent the accidental cross join by forgetting the join predicates as a where clause.

Answer 2

Here is an example of the comment I left, for clarity.
Essentially, try removing the subgroup_cursor altogether by creating the same population in a temp table:
DECLARE #rangeinfoid int
DECLARE #CurrentYear smallint
DECLARE #Percentage float
CREATE TABLE #temp_subgroup
(
RangeInformationID int
)
INSERT INTO #temp_subgroup
(RangeInformationID)
SELECT distinct a.RangeInformationId
FROM SubgroupRange a, DiscountGroupRange b
where a.RangeInformationId = b.RangeInformationId
DECLARE rangeperc_cursor CURSOR FOR
SELECT CurrentYear,
Percentage,
RangeInformationID
from RangePercentage
where RangeInformationId IN (SELECT RangeInformationID FROM #temp_subgroup)
OPEN rangeperc_cursor
WHILE (##FETCH_STATUS <> 0)
BEGIN
FETCH NEXT FROM rangeperc_cursor INTO #rangeinfoid, #CurrentYear, #Percentage
CREATE TABLE #temp_rangeupdate
(
RangeInformationID int,
LowerLimit money,
UpperLimit money
)
INSERT INTO #temp_rangeupdate
( RangeInformationID, LowerLimit, UpperLimit)
SELECT RangeInformationID,
LowerLimit,
UpperLimit
FROM RangeInformation
WHERE RangeInformationID = #rangeinfoid
-- UPDATE/INSERT #temp_rangeupdate
-- UPDATE/INSERT Production Tables from #temp_rangeupdate
DROP TABLE #temp_rangeupdate
END
DROP TABLE #temp_subgroup
CLOSE rangeperc_cursor
DEALLOCATE rangeperc_cursor