Is it possible to group by a combination of rows? - sql

Question

I have a result that gives me a range of values to query from my database:
Start End
----- ---
1 3
5 6
137 139
From those, I need to query the database for the records in that range, which might return something like:
Id Name
----- ------
1 foo
2 bar
3 baz
Id Name
----- ------
5 foo
6 baz
Id Name
----- ------
137 foo
138 bar
139 baz
I want to group the result of those, keeping any of the id ranges since they correlate to the same thing. For example, 1-3 is the same as 137-139, so it would have a count of 2, but of course, the 'range' can be either of the 2:
RangeStart RangeEnd Count
---------- -------- -----
137 139 2
5 6 1
Also note that the order should change the grouping, so foo/bar/baz is not the same as foo/baz/bar.
How can this be accomplished?
EDIT: I have the beginning result (start,end) and I only care about the end result (RangeStart,RangeEnd,Count). I don't actually need the intermediate results, I just use them as explanation.

Answer 1

Here are two queries:
The first one concatenates the strings
into groups based on the ranges and
then shows the first range for each
group of strings. It also has the
total number of times the string
appeared.
The second one shows the concatenated
strings and their respective totals.
Setup:
DECLARE #Tags TABLE (
TagID INT,
Tag VARCHAR(3)
)
INSERT #Tags
SELECT 1, 'Foo' UNION ALL
SELECT 2, 'Bar' UNION ALL
SELECT 3, 'Baz' UNION ALL
SELECT 4, 'Foo' UNION ALL
SELECT 5, 'Bar' UNION ALL
SELECT 6, 'Baz'
DECLARE #Ranges TABLE (
StartRange INT,
EndRange INT
)
INSERT #Ranges
SELECT 1,3 UNION ALL
SELECT 2,3 UNION ALL
SELECT 3,4 UNION ALL
SELECT 4,6
Query To Show First Ranges and Results:
/* Get the first start and end ranges with a match and */
/* the total number of occurences of that match */
SELECT
StartRange,
EndRange,
Total
FROM (
SELECT
StartRange,
EndRange,
Csv,
ROW_NUMBER() OVER (PARTITION BY Csv ORDER BY StartRange ASC) AS RowNum,
ROW_NUMBER() OVER (PARTITION BY Csv ORDER BY StartRange DESC) AS Total
FROM (
/* For each range and its associated Tag values, */
/* Concatenate the tags together using FOR XML */
/* and the STUFF function */
SELECT
StartRange,
EndRange,
(
SELECT STUFF(
(SELECT ',' + Tag
FROM #Tags WHERE TagID BETWEEN r.StartRange AND r.EndRange
ORDER BY TagID
FOR XML PATH('')),1,1,'')
) AS Csv
FROM #Ranges r
) t1
) t2
WHERE RowNum = 1
ORDER BY StartRange, EndRange
/* Results */
StartRange EndRange Total
----------- ----------- -----
1 3 2
2 3 1
3 4 1
Query to show concatenanted strings and totals:
/* Get the concatenated tags and their respective totals */
SELECT
Csv,
COUNT(*) AS Total
FROM (
/* For each range and its associated Tag values, */
/* Concatenate the tags together using FOR XML */
/* and the STUFF function */
SELECT
StartRange,
EndRange,
(
SELECT STUFF(
(SELECT ',' + Tag
FROM #Tags WHERE TagID BETWEEN r.StartRange AND r.EndRange
ORDER BY TagID
FOR XML PATH('')),1,1,'')
) AS Csv
FROM #Ranges r
) t1
GROUP BY Csv
ORDER BY Csv
/* Results */
Csv Total
------------ -----------
Bar,Baz 1
Baz,Foo 1
Foo,Bar,Baz 2
String concatentation method courtesy of Jeremiah Peschka