February 5, 2013 at 4:18 am
Dear,
I want to compare string type values between two rows within a table.
Pls help me to do this.
February 5, 2013 at 5:40 am
T-SQL supports all your common comparison operators, e.g.
=
<
>
!= or <>
Comparisons involving two rows might imply the comparison would take place in a WHERE-clause. If you provide table definitions (CREATE TABLE statements), some test data (INSERT INTO statements) and a better idea of what you're trying to do I'd be happy to further help you.
There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato
February 6, 2013 at 3:16 am
Thank you, OPC.THREE
create table T1(
SL int NOT NULL IDENTITY (1, 1),
ISDN varchar(13) NULL,
MSG varchar(50) NULL
)
insert into T1(ISDN,MSG) values ('123','ABC');
insert into T1(ISDN,MSG) values ('123','ABC');
insert into T1(ISDN,MSG) values ('123','XYZ');
insert into T1(ISDN,MSG) values ('124','XYZ');
insert into T1(ISDN,MSG) values ('124','EFG');
Now I wanna compare whether there is any similar row comprising ISDN and MSG columns.
February 6, 2013 at 9:50 am
What is the goal? A set of rows with no duplicates? If so, would you want the row with the max ID? the min ID?
Most importantly, what have you tried so far?
There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato
February 7, 2013 at 4:29 pm
Hi, The way I read it you are looking for not only duplicates but the original row the duplicates duplicated?
If so try this ( I adjusted your code a tad):
create table #T1(
SL int NOT NULL IDENTITY (1, 1),
ISDN varchar(13) NULL,
MSG varchar(50) NULL
)
insert into #T1(ISDN,MSG) values ('123','ABC');
insert into #T1(ISDN,MSG) values ('123','ABC');
insert into #T1(ISDN,MSG) values ('123','XYZ');
insert into #T1(ISDN,MSG) values ('124','XYZ');
insert into #T1(ISDN,MSG) values ('124','EFG');
--extra duplicate added for better illustration
insert into #T1(ISDN,MSG) values ('123','ABC');
WITH CTE AS (
select row_number() over(partition by isdn, msg order by isdn, msg) as instanceNumber,
SL, ISDN, MSG
from #t1
)
select lt.* from cte as lt inner join (select * from cte where instanceNumber=2) as rt
on lt.isdn=rt.isdn and lt.msg=rt.msg and lt.instanceNumber=1
union all
select * from cte where instanceNumber>1
drop table #t1
----------------------------------------------------
February 8, 2013 at 9:08 am
Another solution that uses left join and a [ARE_THE_SAME] column to mark the columns having same values, you can modify the comparison logic based on what you want to achieve.
The left outer join on a.sl<>b.sl have similar results to a cross join but does not return the same matching rows. a cross join for the example would return 5*5=25 rows the outer returns 5*4=20, the 1-1,2-2,3-3,4-4,5-5 cases does not returned from the join cause of the a.sl<>b.sl .
the outer select is just for filter the cases that we want
select * from
(
select
case when a.isdn=b.isdn and a.msg=b.msg then 'YES' else 'NO' END as [ARE_THE_SAME],a.*
from T1 a
left join T1 b on a.sl<>b.sl
) c
where c.ARE_THE_SAME='YES'
February 8, 2013 at 9:43 am
Johny.B (2/8/2013)
Another solution that uses left join and a [ARE_THE_SAME] column to mark the columns having same values, you can modify the comparison logic based on what you want to achieve.The left outer join on a.sl<>b.sl have similar results to a cross join but does not return the same matching rows. a cross join for the example would return 5*5=25 rows the outer returns 5*4=20, the 1-1,2-2,3-3,4-4,5-5 cases does not returned from the join cause of the a.sl<>b.sl .
the outer select is just for filter the cases that we want
select * from
(
select
case when a.isdn=b.isdn and a.msg=b.msg then 'YES' else 'NO' END as [ARE_THE_SAME],a.*
from T1 a
left join T1 b on a.sl<>b.sl
) c
where c.ARE_THE_SAME='YES'
You can accomplish the same thing with the subselect. Just do the filtering in your join.
select
'Yes' as ARE_THE_SAME,
a.*
from #T1 a
left join #T1 b on a.sl<>b.sl and a.isdn=b.isdn and a.msg=b.msg
where b.sl is not null
Not sure that is the way I would do that but it is simpler.
Given the OP's comment
Now I wanna compare whether there is any similar row comprising ISDN and MSG columns.
Maybe this is what they are after?
select ISDN, MSG, count(*)
from #t1
group by ISDN, MSG
having count(*) > 1
Who really knows? The questions and the follow up description just don't have much detail to work with.
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