TSQL - Merge Group with Range? - tsql

Question

Example code:
Declare #table1 TABLE(myIndex int identity(1,1),[cal] int, Name Nvarchar(20) );
Declare #range int = 5;
INSERT INTO #table1 ([cal], Name)
VALUES (1, 'A'), (3, 'B'), (4, 'C'), (2, 'D'), (3, 'E'), (4, 'F'), (6, 'G'), (2, 'H');
SELECT * FROM #table1
Output:
myIndex | Sum(cal) | Name |
--------+----------+------+
1 | 1 | A |
2 | 3 | B |
3 | 4 | C |
4 | 2 | D |
5 | 3 | E |
6 | 4 | F |
7 | 6 | G |
8 | 2 | H |
I wan to Sum(cal) > 5 then join string
TSQL - 2012 - Report Expect Example
myIndex | Sum(cal) | Name | Description
--------+----------+--------+--------------------------------
1 | 7 | A,B,C | (Explain: First Sum(cal) > 5, Merge String)
2 | 9 | D,E,F | (Explain:Second Sum(cal) > 5, Merge String)
3 | 6 | G | (Explain:Third, Sum(cal) > 5, Merge String)
4 | 2 | H | (Explain:Last, still one last step)
Please, help me to resolve the problems.

Answer 1

This is a solution using a cursor. Hope this could help. Try it and see if performance could be acceptable.
Declare #table1 TABLE(myIndex int identity(1,1),[cal] int, Name Nvarchar(20) );
Declare #range int = 5;
INSERT INTO #table1 ([cal], Name)
VALUES (1, 'A'), (3, 'B'), (4, 'C'), (2, 'D'), (3, 'E'), (4, 'F'), (6, 'G'), (2, 'H');
SELECT * FROM #table1
-----
DECLARE #aggregates TABLE (myIndex int identity(1,1),SumCal int, AggregateNames Nvarchar(MAX) );
DECLARE #SumCal INT
, #AggregateNames NVARCHAR(MAX)
, #cal INT
, #Name Nvarchar(20)
;
SET #SumCal = 0;
SET #AggregateNames = NULL;
DECLARE cur CURSOR LOCAL FAST_FORWARD FOR
SELECT [cal], name from #table1 ORDER BY myIndex
OPEN cur
FETCH NEXT FROM cur INTO #cal, #Name
WHILE ##FETCH_STATUS = 0
BEGIN
SET #SumCal = #SumCal + #cal
SET #AggregateNames = ISNULL(#AggregateNames + ',', '') + #Name
IF #SumCal > 5
BEGIN
INSERT INTO #aggregates([SumCal], AggregateNames)
VALUES(#SumCal, #AggregateNames)
SET #SumCal = 0
SET #AggregateNames = NULL
END
FETCH NEXT FROM cur INTO #cal, #Name
END
IF #SumCal > 0
BEGIN
INSERT INTO #aggregates([SumCal], AggregateNames)
VALUES(#SumCal, #AggregateNames)
END
CLOSE cur
DEALLOCATE cur
SELECT * FROM #aggregates