CODEWITHSUNDEEP
t-sql
sunny
sunny

Reputation: 49

Grouping sets of records in sql

The grouping is done on from and toloc and one group is been indicated by usrid

Table :

from   toloc  usrid
a        b      1
c        d      1       --- group 1
e        f      1
-------------------
a        b      2
c        d      2       --- group 2  
e        f      2
----------------------
a        b      3
c        d      3       --- group 3
h        k      3

after group set query required resulset ??? 

from   toloc  usrid
a        b      1
c        d      1       --- group 1 & 3 combined to form 1 group
e        f      1
-------------------
a        b      2![alt text][1]
c        d      2       --- group 2  
h        k      2

How can I achieve the resultset. I have to group similar set of records in sql. Is it possible to do with rollup or the new grouping sets. I'm not been able to figure it.

Upvotes: 4

Views: 390

Answers (2)

alpav
alpav

Reputation: 3062

Answer to this question is here: https://stackoverflow.com/a/6727662/195446

Another way is to use FOR XML PATH as signature of set of records.

Upvotes: 1

t-clausen.dk
t-clausen.dk

Reputation: 44326

I dug up this old question. Assuming there there are no duplicated rows it should work.

I solved the one you linked to first and rewrote it to match this one, so the fields will differ in names compared to your example.

DECLARE @t TABLE (fromloc VARCHAR(30), toloc VARCHAR(30), usr_history INT)

INSERT @t VALUES ('a', 'b', 1)
INSERT @t VALUES ('c', 'b', 1)
INSERT @t VALUES ('e', 'f', 1)
INSERT @t VALUES ('a', 'b', 2)
INSERT @t VALUES ('c', 'b', 2)
INSERT @t VALUES ('e', 'f', 2)
INSERT @t VALUES ('a', 'b', 3)
INSERT @t VALUES ('c', 'd', 3)
INSERT @t VALUES ('h', 'k', 3)

;WITH c as
(
SELECT t1.usr_history h1, t2.usr_history h2, COUNT(*) COUNT 
FROM @t t1
JOIN @t t2 ON t1.fromloc = t2.fromloc and t1.toloc = t2.toloc and t1.usr_history < t2.usr_history 
GROUP BY t1.usr_history, t2.usr_history
), 
d as (
SELECT usr_history h, COUNT(*) COUNT FROM @t GROUP BY usr_history
), 
e as (
SELECT d.h FROM d JOIN c ON c.COUNT = d.COUNT and c.h2 = d.h
JOIN d d2 ON d2.COUNT=c.COUNT and d2.h= c.h1
)
SELECT fromloc, toloc, DENSE_RANK() OVER (ORDER BY usr_history) AS 'usrid' 
FROM @t t 
WHERE NOT EXISTS (SELECT 1 FROM e WHERE e.h = t.usr_history)

Upvotes: 1

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