plsql for inserting a table - oracle

Question

declare
dno number(4);
dname varchar2(5);
ddate date;
dbasic number(10);
djob varchar2(15);
dcomm number(5);
dept number(5);
dmgr number(5);
begin
select empno,ename,hiredate,sal,job1,comm,deptno,mgr
into dno,dname,ddate,dbasic,djob,dcomm,dept,dmgr
from emp
where empno=&userno;
if sql%rowcount>0
then
insert into newempl
values(dno,dname,djob,dmgr,ddate,dbasic,dcomm,dept);
dbms_output.put_line('records inserted into it');
dbms_output.put_line(dno||' '||dname||' '||ddate||' '||dbasic);
end if;
end;
Error report:
ORA-01858: a non-numeric character was found where a numeric was expected
ORA-06512: at line 19
01858. 00000 - "a non-numeric character was found where a numeric was expected"
*Cause: The input data to be converted using a date format model was
incorrect. The input data did not contain a number where a number was
required by the format model.
*Action: Fix the input data or the date format model to make sure the
elements match in number and type. Then retry the operation.
I do not understand what the error is.

Answer 1

From the error message it looks like you're inserting values into the wrong columns. Without seeing your table structure (from describe newmpl for example) this is a bit of a guess, but this statement:
insert into newempl
values(dno,dname,djob,dmgr,ddate,dbasic,dcomm,dept);
... is assuming that the columns in the newempl table are in a certain order, which may not be (and appears to not be) the case. More specifically here, I think it's complaining about hiredate, as you're implicitly putting the djob value in that column - assuming the new table looks like emp - and the djob value can't be converted into a date.
Update based on comment: from how you said you created the table, this is equivalent to:
insert into newempl(dno, dname, ddate, dbasic, djob, dcomm, dept, dmgr)
values(dno,dname,djob,dmgr,ddate,dbasic,dcomm,dept);
... so as you can see when it's laid out like that the columns are not aligned, and you are indeed trying to put your djob value into the ddate column, which won't work.
It is always safer to explicitly specify the columns, both to prevent problems with different ordering in different environments (though that shouldn't really happen with controlled code) and to prevent this breaking if a new column is added. Something like:
insert into newempl(empno,ename,jon1,mgr,hiredate,sal,comm,deptno)
values(dno,dname,djob,dmgr,ddate,dbasic,dcomm,dept);
As an aside, when declaring your local variables you could specify them based on the table, for example dno emp.empno%TYPE. And as another aside based on your comment, I'd recommend giving local variables different names to the table columns to avoid confusion.
As a_horse_with_no_name said, this can be done with a simple SQL insert, and even within a PL/SQL block it doesn't need separate select and insert statements; you could just do:
insert into newempl(empno,ename,jon1,mgr,hiredate,sal,comm,deptno)
select empno,ename,jon1,mgr,hiredate,sal,comm,deptno
from emp
where empno=&userno;
Unfortunately none of this addresses the requirement that 'the employees who are managers must be inserted into new table', since you aren't doing anything with the mgr column. I don't think it would be constructive to do that part of the task for you at this point though, and I'm not sure where &userno fits in to that.