Max with distinct two columns and corresponding third column

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Max with distinct two columns and corresponding third column

stsniper

SSC Rookie

Points: 41
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April 30, 2014 at 12:13 pm

#290775

Hi, i need to write a query and can't get it to work no matter how it try. Here's what i need:
T1
-------
a1
a2
datetime
a4
a5
.....
i need distinct max between a1&a2 which i can get no problem but i cant get that unique datetime that correspond to a1&a2 in 1 query because this is will a subquery in a big query. Creating another temp table etc is not an option for me. Is there any way to do it?
PS.
for every specific a1 there is many entries of a2 + timedate etc.
create table abc_test (
id int
,runs int
,date1 datetime
)
insert into abc_test (
id
,runs
,date1
) values
('24','1','2013-12-05 10:00:01.000'),
('24','2','2013-12-05 10:00:02.000'),
('25','1','2013-12-05 10:00:03.000'),
('25','2','2013-12-05 10:00:04.000'),
('25','3','2013-12-05 10:00:06.000'),
('26','1','2013-12-05 10:00:07.000'),
('26','2','2013-12-05 10:00:08.000'),
('21','1','2013-12-05 10:00:09.000')
id runs date1
----------- ----------- -----------------------
24 1 2013-12-05 10:00:01.000
24 2 2013-12-05 10:00:02.000
25 1 2013-12-05 10:00:03.000
25 2 2013-12-05 10:00:04.000
25 3 2013-12-05 10:00:06.000
26 1 2013-12-05 10:00:07.000
26 2 2013-12-05 10:00:08.000
27 1 2013-12-05 10:00:09.000
(8 row(s) affected)
Expected Result
id runs date1
----------- ----------- -----------------------
24 2 2013-12-05 10:00:02.000
25 3 2013-12-05 10:00:06.000
26 2 2013-12-05 10:00:08.000
27 1 2013-12-05 10:00:09.000
I can either get distinct ID + latest date or ID + largest #ofRuns, both will do but also need the third column.
Thanks in advance

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Sean Lange SSC Guru Points: 286590 More actions · Answer 1

Hi and welcome to the forums. In order to help we will need a few things:

1. Sample DDL in the form of CREATE TABLE statements

2. Sample data in the form of INSERT INTO statements

3. Expected results based on the sample data

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thava SSCrazy Points: 2275 More actions · Answer 2

May be this will help you

declare @abc_test as table (

id int ,runs int ,date1 datetime

)

insert into @abc_test ( id ,runs ,date1 )

values

('24','1','2013-12-05 10:00:01.000'),

('24','2','2013-12-05 10:00:02.000'),

('25','1','2013-12-05 10:00:03.000'),

('25','2','2013-12-05 10:00:04.000'),

('25','3','2013-12-05 10:00:06.000'),

('26','1','2013-12-05 10:00:07.000'),

('26','2','2013-12-05 10:00:08.000'),

('21','1','2013-12-05 10:00:09.000');

WITH cte AS (

SELECT ROW_NUMBER() OVER(PARTITION BY id ORDER BY Runs DESC) rn,*

FROM @abc_test

)

SELECT * FROM CTE

WHERE RN =1

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bkmsmith Ten Centuries Points: 1132 More actions · Answer 3

Here is another option.

create table abc_test

(

id int

,runs int

,date1 datetime

)

;

insert into abc_test

(

id

,runs

,date1

) values

('24','1','2013-12-05 10:00:01.000'),

('24','2','2013-12-05 10:00:02.000'),

('25','1','2013-12-05 10:00:03.000'),

('25','2','2013-12-05 10:00:04.000'),

('25','3','2013-12-05 10:00:06.000'),

('26','1','2013-12-05 10:00:07.000'),

('26','2','2013-12-05 10:00:08.000'),

('27','1','2013-12-05 10:00:09.000')

;

SELECTT2.id

, [runs] = T2.MaxRuns

, T1.date1

FROMdbo.abc_test T1

INNER JOIN

(

SELECTid

, [MaxRuns] = MAX(runs)

FROMdbo.abc_test

GROUP BY id

) T2

ON T1.id = T2.id AND T1.runs = T2.MaxRuns

ORDER BY T2.id

;

Regards,

Brian

Sean Lange SSC Guru Points: 286590 More actions · Answer 4

bkmsmith (5/6/2014)
Here is another option.
create table abc_test
(
id int
,runs int
,date1 datetime
)
;
insert into abc_test
(
id
,runs
,date1
) values
('24','1','2013-12-05 10:00:01.000'),
('24','2','2013-12-05 10:00:02.000'),
('25','1','2013-12-05 10:00:03.000'),
('25','2','2013-12-05 10:00:04.000'),
('25','3','2013-12-05 10:00:06.000'),
('26','1','2013-12-05 10:00:07.000'),
('26','2','2013-12-05 10:00:08.000'),
('27','1','2013-12-05 10:00:09.000')
;
SELECTT2.id
, [runs] = T2.MaxRuns
, T1.date1
FROMdbo.abc_test T1
INNER JOIN
(
SELECTid
, [MaxRuns] = MAX(runs)
FROMdbo.abc_test
GROUP BY id
) T2
ON T1.id = T2.id AND T1.runs = T2.MaxRuns
ORDER BY T2.id
;
Regards,
Brian

That should return the correct data but you are hitting the table twice instead of once. Performance wise this is going to be slower.