Generating Unique Keys

Question

I am trying to add an additional column to a select which will act as an Unique key.
Is there any way I can use a sequence generator to the query.

Answer 1

user610910 wrote:
I am trying to add an additional column to a select which will act as an Unique key.
Is there any way I can use a sequence generator to the query.If you are not using ORDER BY, plain ROWNUM will do:
SQL> select rownum,ename from emp
  2  /
    ROWNUM ENAME
         1 SMITH
         2 ALLEN
         3 WARD
         4 JONES
         5 MARTIN
         6 BLAKE
         7 CLARK
         8 SCOTT
         9 KING
        10 TURNER
        11 ADAMS
    ROWNUM ENAME
        12 JAMES
        13 FORD
        14 MILLER
14 rows selected.
SQL> If you use ORDER BY, you could wrap select:
SQL> select  rownum,
  2          ename
  3    from  (
  4           select  ename
  5             from  emp
  6             order by ename
  7          )
  8  /
    ROWNUM ENAME
         1 ADAMS
         2 ALLEN
         3 BLAKE
         4 CLARK
         5 FORD
         6 JAMES
         7 JONES
         8 KING
         9 MARTIN
        10 MILLER
        11 SCOTT
    ROWNUM ENAME
        12 SMITH
        13 TURNER
        14 WARD
14 rows selected.
SQL> SY.