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Select and Display Duplicate Records

Posted on 2008-09-30
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Last Modified: 2012-05-05
I need to select and display using SQL duplicate records from the following table

bomparent  bompos
12                 1
12                  2
13                 1
13                  2
12                  1
12                  2
13                 3

I need to return
12       1
12       2
12       1
12        2

from the above table.

Thanks
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Comment
Question by:RickCooper
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7 Comments
 
LVL 39

Expert Comment

by:BrandonGalderisi
ID: 22605688
The first query will only what is duplicated, not every duplicate record
12    1
12    2


the second query will return all items that have duplicates
12    1
12    2
12    1
12    2


select bomparent,bompos
from YourTable
group by bomparent,bompos
having count(*)>1
 
 
GO
 
select a.* from YourTable
join 
(select bomparent,bompos
from YourTable
group by bomparent,bompos
having count(*)>1) b
on a.bomparent = b.bomparent
and a.bompos = b.bompos

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0
 
LVL 1

Author Comment

by:RickCooper
ID: 22605758
Hi BrandonGalderisi
The second query is what is required as I need to delete the duplicates. However it fails with The column prefix 'a' does not match with a table name or alias name used in the query.

0
 
LVL 39

Accepted Solution

by:
BrandonGalderisi earned 2000 total points
ID: 22606051
oops...

forgot the alias after "YourTable" which you obviously need to replace with your actual table name.
select a.* from YourTable a
join 
(select bomparent,bompos
from YourTable
group by bomparent,bompos
having count(*)>1) b
on a.bomparent = b.bomparent
and a.bompos = b.bompos

Open in new window

0
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LVL 1

Author Closing Comment

by:RickCooper
ID: 31501550
Spot on. Thanks very much.
I now have over 17000 records to delete.
0
 
LVL 39

Expert Comment

by:BrandonGalderisi
ID: 22606450
So you are deleting one of the two I assume.  And you're not on SQL 2000 by chance are you?
0
 
LVL 39

Expert Comment

by:BrandonGalderisi
ID: 22606456
Sorry....

And you're not on SQL "2005" by chance are you?
0
 
LVL 1

Author Comment

by:RickCooper
ID: 22606545
I'm deleting one of the two and I'm on SQL2000
0

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