Question. Eliminating duplicate identical rows.

Question

Question. Eliminating duplicate identical rows.
--1. assume we have this table
create table T
tabid int not null,
crdate datetime not null
go
--2.Now load the following data:
insert into T values (1, '1/1/2003')
insert into T values (1, '1/1/2003')
insert into T values (2, '2/1/2003')
insert into T values (2, '2/1/2003')
insert into T values (3, '3/1/2003')
insert into T values (3, '3/1/2003')
insert into T values (4, '4/1/2003')
insert into T values (4, '4/1/2003')
go
-- 3. Run this query to discover duplicates
select tabid, crdate, count(*)
from T
group by tabid, crdate
having count(*) > 1
go
--4. Result is something like this
1     2003-01-01 00:00:00.000     2
2     2003-02-01 00:00:00.000     2
3     2003-03-01 00:00:00.000     2
4     2003-04-01 00:00:00.000     2
Question
How do I eliminate duplicates and reduce table by 50%?

Answer 1

I think this what you want:
SQL> create table test ( c1 varchar2(5));
Table created.
SQL> insert into test values ( 'a' );
1 row created.
SQL> insert into test values ( 'b');
1 row created.
SQL> insert into test values ( 'a');
1 row created.
SQL> insert into test values ( 'c');
1 row created.
SQL>
SQL> select c1 from test group by c1 having count(*)>1;
C1
a
SQL> delete from test where c1 in
2 ( select c1 from test group by c1 having count(*)>1);
2 rows deleted.
SQL>
SQL> select * from test;
C1
b
c
SQL>
Joel P�rez