Showing posts with label starttime. Show all posts
Showing posts with label starttime. Show all posts

Thursday, March 22, 2012

Compute sum of count(*) with group by

Hi,
Given the following table and test data:
CREATE TABLE test (
recordId numeric(18, 0) NOT NULL,
spId int NOT NULL,
startTime datetime NULL,
endTime datetime NULL )
INSERT INTO test VALUES (1,1,'2005-01-01 12:00','2005-01-01 14:33')
INSERT INTO test VALUES (2,2,'2005-01-01 12:26','2005-01-01 14:00')
INSERT INTO test VALUES (3,1,'2005-01-01 14:00','2005-01-01 14:33')
INSERT INTO test VALUES (4,2,'2005-01-01 14:00','2005-01-01 15:15')
INSERT INTO test VALUES (5,1,'2005-01-01 15:15','2005-01-01 15:20')
INSERT INTO test VALUES (6,2,'2005-01-01 15:15','2005-01-01 16:00')
INSERT INTO test VALUES (7,3,'2005-01-01 12:00','2005-01-01 14:30')
the following query lists only the spid's with non-unique spid's and
their respective counts:
SELECT spid, count(*) AS 'Count'
FROM test
GROUP BY spid
HAVING count(*) > 1 ORDER BY spid
I'm new to SQL and am having difficulty with a couple of things:
1. Modify the above query to compute the grand total for the Count, or
indeed a separate SQL statement to return just the grand total (= 6 in
this example).
2. This is the big challenge :). Taking the grouping returned by the
above query, write a query/stored procedure which looks for records
with identical spId's and the endtime of one spid equal to the
startTime of another. With the above test data, recordIds 3, 5, and 2,
4, 6 match this criteria.
Thanks very much for any help with this.1. Use a derived table construct:
SELECT SUM( total )
FROM ( SELECT spid, COUNT(*)
FROM tbl
GROUP BY spid
HAVING COUNT(*) > 1 ) D ( spid, total ) ;
2. Not sure if your requirements are clear since . Something like:
SELECT recordId, spId, ...
( SELECT MIN( t2.startTime )
FROM tbl t2 WHERE t2.spId = t1.spId
AND t2.startTime >= t1.endtime )
FROM tbl t1
ORDER BY t1.spid, startTime ;
If, not please post the sample resultset for the dataset you posted.
Anith|||Anith Sen wrote:
> 1. Use a derived table construct:
> SELECT SUM( total )
> FROM ( SELECT spid, COUNT(*)
> FROM tbl
> GROUP BY spid
> HAVING COUNT(*) > 1 ) D ( spid, total ) ;
>
Thanks. What does the 'D' mean above?

> 2. Not sure if your requirements are clear since . Something like:
> SELECT recordId, spId, ...
> ( SELECT MIN( t2.startTime )
> FROM tbl t2 WHERE t2.spId = t1.spId
> AND t2.startTime >= t1.endtime )
> FROM tbl t1
> ORDER BY t1.spid, startTime ;
> If, not please post the sample resultset for the dataset you posted.
CREATE TABLE test (
recordId numeric(18, 0) NOT NULL,
spId int NOT NULL,
startTime datetime NULL,
endTime datetime NULL )
INSERT INTO test VALUES (1,1,'2005-01-01 12:00','2005-01-01 14:33')
INSERT INTO test VALUES (3,1,'2005-01-01 14:00','2005-01-01 14:33')
INSERT INTO test VALUES (5,1,'2005-01-01 14:33','2005-01-01 15:20')
INSERT INTO test VALUES (2,2,'2005-01-01 12:26','2005-01-01 14:00')
INSERT INTO test VALUES (4,2,'2005-01-01 14:00','2005-01-01 15:15')
INSERT INTO test VALUES (6,2,'2005-01-01 15:15','2005-01-01 16:00')
INSERT INTO test VALUES (7,3,'2005-01-01 12:00','2005-01-01 14:30')
(Sorry, no wonder it wasn't clear as there was mistake in my original
test data. I've corrected the data above and put records with the same
spId together to make the grouping more obvious.)
So, from the above test data the expected results contain 2 sets of
matching data:
1. recordIds 3 and 5 because they have the same spId (1) and the
endTime of recordId 3 is the same as the startTime of recordId 5.
2. recordIds 2, 4 and 6 because they have the same spId (2) and the
endTime of recordId 2 is the same as the startTime of recordId 4; the
endTime of 4 is the same as the startTime of 6.
I hope that makes sense now. cheers,|||On 11 Nov 2005 09:30:25 -0800, "J Williams"
<johnwilliams_esquire@.hotmail.com> wrote:
>SELECT spid, count(*) AS 'Count'
>FROM test
>GROUP BY spid
WITH ROLLUP
>HAVING count(*) > 1 ORDER BY spid
If that does the job, great, otherwise you can always store the
results of the first query in a table an do further summations against
it.
J.|||>SELECT spid, count(*) AS 'Count'
>FROM test
>GROUP BY spid
WITH ROLLUP
>HAVING count(*) > 1 ORDER BY spid
Thanks, but that doesn't give the expected result. The basic SELECT:
SELECT spid, count(*) AS 'Count'
FROM test
GROUP BY spid
HAVING count(*) > 1 ORDER BY spid
returns:
spid Count
1 3
2 3
The grand total of Count in the above resultset is 6 and the SQL posted
earlier by Anith Sen gives this result:
SELECT SUM( total )
FROM ( SELECT spid, COUNT(*)
FROM tbl
GROUP BY spid
HAVING COUNT(*) > 1 ) D ( spid, total )|||>> What does the 'D' mean above?
D in the query stands for an alias for the derived table ( some folks
explicitly use AS keyword before the alias as well. )
Can you post the sample resultset here ( as you'd want to see on the QA
results pane ).
Anith|||Anith Sen wrote:

> Can you post the sample resultset here ( as you'd want to see on the QA
> results pane ).
First recordId, Second recordId, spId, endTime, startTime
3 5 1 2005-01-01 14:33 2005-01-01 14:33
2 4 2 2005-01-01 14:00 2005-01-01 14:00
4 6 2 2005-01-01 15:15 2005-01-01 15:15
The resultset shows pairs of 'matching' records, which is slightly
different (and better) to how I first envisioned it.
Thanks.|||This is one way of getting it:
SELECT MAX( t1.recordid ),
t2.recordid, t1.spid, t1.endtime
FROM test t1
INNER JOIN test t2
ON t1.spId = t2.spId
AND t1.endTime = t2.starttime
GROUP BY t1.spid, t2.recordid, t1.endtime ;
Anith|||That's excellent, thanks.