How to find records with the same field?

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Hi,

On Tue, 20 Jul 2004, Joost Kraaijeveld wrote:

I have a table with column1, column2, column3 and column4. How do I get
all records, sorted by column4 that have the same column1,column2 and
column3?

SELECT * from table_name WHERE (c1=c2) AND (c2=c3) ORDER BY c4;

will work, I think:
===================
test=> CREATE TABLE joost (c1 varchar(10), c2 varchar(10), c3 varchar(10),
c4 varchar(10));
CREATE TABLE
test=> INSERT INTO joost VALUES ('test1','test1','test1','remark');
INSERT 1179458 1
test=> INSERT INTO joost VALUES ('test1','test1','test1','remark2');
INSERT 1179459 1
test=> INSERT INTO joost VALUES ('test1','test2','test3','nevermind');
INSERT 1179460 1
test=> SELECT * from joost ;
c1 | c2 | c3 | c4
- -------+-------+-------+-----------
test1 | test1 | test1 | remark
test1 | test1 | test1 | remark2
test1 | test2 | test3 | nevermind
(3 rows)

test=> SELECT * from joost WHERE (c1=c2) AND (c2=c3) ORDER BY c4
test-> ;
c1 | c2 | c3 | c4
- -------+-------+-------+--------
test1 | test1 | test1 | remark
test1 | test1 | test1 | remark
(2 rows)
===================

Regards,

- --
Devrim GUNDUZ
devrim~gunduz.org devrim.gunduz~linux.org.tr
http://www.tdmsoft.com
http://www.gunduz.org
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Hi joost,

I think the following should work:

include the table 2 times in your query and join the two instances in
the query by the 3 columns.

Example:

Select
t1. column4, t1.column1, t1.column2, t1.column3
From
yourtable t1, yourtable t2
Where
t1.column1 = t2.column1
and t1.column2 = t2.column2
and t1.column3 = t2.column3
order by
t1.column4;

-----Ursprüngliche Nachricht-----
Von: pgsql-general-owner@postgresql.org [mailto:pgsql-general-
owner@postgresql.org] Im Auftrag von Joost Kraaijeveld
Gesendet: Dienstag, 20. Juli 2004 11:39
An: pgsql-general@postgresql.org
Betreff: [GENERAL] How to find records with the same field?

I have a table with column1, column2, column3 and column4. How do I get

all

records, sorted by column4 that have the same column1,column2 and

column3?

TIA

Joost

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broadcast)---------------------------TIP

Thanks everyone for answering. Apparently my question was not clear enough.

I want something like this:

select col1, col2,col3, col4
from table1
where
col1 =col1 and
col2 = col2 and
col3 = col3
order by col4

But if I run this query I get all the records in the table and not just the (double) ones with the same columns.

TIA

Joost

You can find the duplicates with a self-join:

select t1.col1, t1.col2, t1.col3, t1.col4
from table1 as t1, table1 as t2
where
t1.oid != t2.oid
t1.col1 = t2.col1 and
t1.col2 = t2.col2 and
t1.col3 = t2.col3
order by t1.col4;

Joost Kraaijeveld schrieb:

Sorry, iI frogot an "and" after "1.oid != t2.oid"

select t1.col1, t1.col2, t1.col3, t1.col4
from table1 as t1, table1 as t2
where
t1.oid != t2.oid AND
t1.col1 = t2.col1 and
t1.col2 = t2.col2 and
t1.col3 = t2.col3
order by t1.col4;