Help on decode

Question

Hi,
I am trying out a where clause for forms which should satisfy the following condtions:
1.if the variable(:var) is null that is by default it should display all the records.
2.if the variable is selected then the rows should be selected which begin with the value of the variable.
I am giving an example and the queries below:
select * from emp where ename in
decode(:var,null,ename,(select ename from emp where ename like :var||'%'))
as above if :var is null then all the rows must be selected else the rows beginning with :var must be selected.
I encounter the followinf error:
ORA--01427:single-row subquery returns more than one row.
can any1 pls help me with the decode.
Thanks a heap
vinayak

Answer 1

SQL> variable v_var char
SQL>
SQL> begin
  2    :v_var:='A';
  3  end;
  4  /
PL/SQL procedure successfully completed.
SQL>
SQL> select empno, ename from emp
  2  where ename like :v_var||'%';
     EMPNO ENAME
      7499 ALLEN
      7876 ADAMS
SQL>
SQL> begin
  2    :v_var:=NULL;
  3  end;
  4  /
PL/SQL procedure successfully completed.
SQL>
SQL> select empno, ename from emp
  2  where ename like :v_var||'%';
     EMPNO ENAME
      7369 SMITH
      7499 ALLEN
      7521 WARD
      7566 JONES
      7654 MARTIN
      7698 BLAKE
      7782 CLARK
      7788 SCOTT
      7839 KING
      7844 TURNER
      7876 ADAMS
      7900 JAMES
      7902 FORD
      7934 MILLER
14 rows selected.
SQL>