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:: Rownum in postgresql ::

Hi All,

As we know,we can generate rownum with window fuctions also(Rank).In oracle we have "rownum" pseduo column,but we don't in postgresql.
Here is the one of the solution for generating rownum in postgresql.

In Oracle
-----------

SQL> CREATE SEQUENCE ROWNUMSEQ;

Sequence created.


SQL> SELECT EMPNO,ROWNUMSEQ.NEXTVAL AS "ROWNUM" FROM EMP;

EMPNO ROWNUM
---------- ----------
7369 1
7499 2
7521 3
7566 4
7654 5
7698 6
7782 7
7788 8
7839 9
7844 10
7876 11
7900 12
7902 13
7934 14


In PostgreSQL
----------------

postgres=# CREATE SEQUENCE ROWNUMSEQ;
CREATE SEQUENCE

postgres=# CREATE TABLE TEST(T INT);
CREATE TABLE

postgres=# INSERT INTO TEST VALUES(GENERATE_SERIES(1,14));
INSERT 0 14


postgres=# SELECT T,NEXTVAL('ROWNUMSEQ') AS ROWNUM FROM TEST;
t | rownum
----+--------
1 | 1
2 | 2
3 | 3
4 | 4
5 | 5
6 | 6
7 | 7
8 | 8
9 | 9
10 | 10
11 | 11
12 | 12
13 | 13
14 | 14

--Dinesh

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