Using cursor to loop through a table variable in SQL Server - sql

Question

I have a parameter of a stored procedure which gets some data in the format
1/1/2018-2/1/2018,2/1/2018-3/1/2018,3/1/2018-4/1/2018,4/1/2018-5/1/2018,5/1/2018-6/1/2018,6/1/2018-7/1/2018,7/1/2018-8/1/2018,8/1/2018-9/1/2018,9/1/2018-10/1/2018,
10/1/2018-11/1/2018,11/1/2018-12/1/2018,12/1/2018-12/31/2018
I have a function which splits the data based on the , character and stores the results into a table variable as shown here:
declare #SPlitDates table(ItemNumber int, Item nvarchar(max))
insert into #SPlitDates
select *
from dbo.SPlitFunction(#RequestData, ',')
After this I have to perform certain operations on the data range so I use cursors to loop through the temp table as shown below
DECLARE cur CURSOR FOR
SELECT Item
FROM #SPlitDates
ORDER BY ItemNumber
OPEN cur
FETCH NEXT FROM cur INTO #monthStart
WHILE ##FETCH_STATUS = 0
BEGIN
-- Some operation
END
The max data points that I will get in the temp table is the date range for 12 months.
My question is that could I be using something else apart from cursors to improve performance or it doesn't matter when the dataset is really this small.
Thanks
Edit - To show operation inside the cursor
declare #SPlitDates table(ItemNumber int, Item nvarchar(max))
insert into #SPlitDates
select *
from dbo.SPlitFunction(#RequestData, ',')
declare #SPlitDatesData table (ItemNumber varchar(100), Item nvarchar(max))
declare #SPlitDatesAvgData table(Code nvarchar(100), Val decimal(18,2))
declare #dataFilter as nvarchar(max),
#SQL as nvarchar(max);
declare #monthStart nvarchar(100)
declare #count int
set #count = 0
--Declaring a cursor to loop through all the dates as defined in the requested quarter
DECLARE cur CURSOR FOR
SELECT Item
FROM #SPlitDates
ORDER BY ItemNumber
OPEN cur
FETCH NEXT FROM cur INTO #monthStart
WHILE ##FETCH_STATUS = 0
BEGIN
DECLARE #Period NVARCHAR(100)
SET #Period = #monthStart
INSERT INTO #SPlitDatesData
--split the dates to get the start and the end dates
SELECT *
FROM dbo.SPlitFunction(#Period, '-')
DECLARE #PeriodStart NVARCHAR(100)
DECLARE #PeriodEnd NVARCHAR(100)
SET #PeriodStart = (SELECT Item FROM #SPlitDatesData WHERE ItemNumber = 1)
SET #PeriodEnd = (SELECT Item FROM #SPlitDatesData WHERE ItemNumber = 2)
DELETE FROM #SPlitDatesData
--add the start and end dates to the filter
SET #dataFilter = 'StatusDate between convert(datetime,('''+#PeriodStart+'''))
and DATEADD(dy, 1, convert(datetime,('''+#PeriodEnd+''')))'
SET #count = #count +1;
SET #SQL = 'INSERT INTO #BidAverageCycleCalculation (SortOrder, Code, Data)
VALUES (#count,
''SL Payroll'',(select dbo.GetAverageCycleBetweenBids('''+#PeriodStart+''',
'''+#PeriodEnd+''',''SL''))
)'
EXEC SP_ExecuteSQL #SQL, N'#count int', #count;
SET #count = #count +1;
SET #SQL = 'INSERT INTO #BidAverageCycleCalculation (SortOrder, Code, Data)
VALUES (#count,
''GV Payroll'',(select dbo.GetAverageCycleBetweenBids('''+#PeriodStart+''',
'''+#PeriodEnd+''',''GV''))
)'
EXEC SP_ExecuteSQL #SQL , N'#count int', #count;
SET #count = #count +1;
SET #SQL = 'Insert into #BidAverageCycleCalculation (SortOrder,Code,Data)
Values (#count,
''Global Payroll'',(select dbo.GetAverageCycleBetweenBids('''+#PeriodStart+''',
'''+#PeriodEnd+''',''GVS''))
)'
EXEC SP_ExecuteSQL #SQL, N'#count int', #count;
SET #count = #count +1;
SET #SQL = 'Insert into #BidAverageCycleCalculation (SortOrder,Code,Data)
Values (#count,
''TimeHCM'',(select dbo.GetAverageCycleBetweenBids('''+#PeriodStart+''',
'''+#PeriodEnd+''',''Time''))
)'
EXEC SP_ExecuteSQL #SQL, N'#count int', #count;
delete from #SPlitDatesAVgData
FETCH NEXT FROM cur INTO #monthStart
END
CLOSE cur
DEALLOCATE cur

Answer 1

This uses two parts - first convert your string into a table, then do bulk inserts into your destination. No need for cursors.
** Please excuse any syntax errors as I'm doing it without access to your actual tables or functions so cant test it, but you get the idea
declare #in varchar(max)
set #in= '1/1/2018-2/1/2018,2/1/2018-3/1/2018,3/1/2018-4/1/2018,4/1/2018-5/1/2018,5/1/2018-6/1/2018,6/1/2018-7/1/2018,7/1/2018-8/1/2018,8/1/2018-9/1/2018,9/1/2018-10/1/2018,10/1/2018-11/1/2018,11/1/2018-12/1/2018,12/1/2018-12/31/2018'
declare #xml xml;
set #xml= convert(xml,'<r><f>'+replace(replace(#in,',','</t></r><r><f>'),'-','</f><t>') +'</t></r>')
declare #t table(id int identity, f date, t date)
insert #t
select
Tbl.Col.value('f[1]', 'date') f,
Tbl.Col.value('t[1]', 'date') t
FROM #xml.nodes('//r') Tbl(Col)
select * from #t
declare #count int;
select #count=count(*) from #t
INSERT INTO #BidAverageCycleCalculation (SortOrder, Code, Data)
select id, 'SL Payroll',(select dbo.GetAverageCycleBetweenBids(f,t,'SL')) from #t
INSERT INTO #BidAverageCycleCalculation (SortOrder, Code, Data)
select id+#count,'GV Payroll',(select dbo.GetAverageCycleBetweenBids(f,t,'GV')) from #t
INSERT INTO #BidAverageCycleCalculation (SortOrder, Code, Data)
select id+#count*2,'Global Payroll',(select dbo.GetAverageCycleBetweenBids(f,t,'GVS')) from #t
INSERT INTO #BidAverageCycleCalculation (SortOrder, Code, Data)
select id+#count*3,'TimeHCM',(select dbo.GetAverageCycleBetweenBids(f,t,'Time')) from #t