Column alias error in a query of views

Question

Hi
I was trying to workout this query
create view dept_sal as
select d.department_name,sum(e.salary)
from departments d left outer join employees e
on d.department_id= e.department_id
group by d.department_name;
and i recieved this error message .............
Error at Command Line:2 Column:25
Error report:
SQL Error: ORA-00998: must name this expression with a column alias
00998. 00000 - "must name this expression with a column alias"
*Cause:   
*Action:
I tried to put an alias for sum(e.salary) function and it worked but i dont understand why it is required or is the problem somewhere else and why an alias is needed here ???
Actually the book hasnt specfied the need for an alias at this place ...so i wanted to know why am getting this error ..
create or replace view dept_sal as
select d.department_name,sum(e.salary) as d_sal
from departments d left outer join employees e
on d.department_id= e.department_id
group by d.department_name;
view DEPT_SAL created.
Also i wanted to know if i can start a thread each time i want have a problem or can i add my questions to somebody
else's thread ..
Thanks
Jayshree

Answer 1

Hi, Jayshree,
to_learn wrote:
Hi
I was trying to workout this query
create view dept_sal as
select d.department_name,sum(e.salary)
from departments d left outer join employees e
on d.department_id= e.department_id
group by d.department_name;
and i recieved this error message .............
Error at Command Line:2 Column:25
Error report:
SQL Error: ORA-00998: must name this expression with a column alias
00998. 00000 - "must name this expression with a column alias"
*Cause:   
*Action:
I tried to put an alias for sum(e.salary) function and it worked but i dont understand why it is required or is the problem somewhere else and why an alias is needed here ???Every column in a table or view must have a unique name. If you don't explicitly specify a name for the output column, Oracle will try to generate one based on the input expression. If the name does not follow the normal rules for identifiers (one of which is that the name can't contain special symbols, like parentheses) then the name must be enclosed in double-quotes.
Notice that these rules are a little different from the rules about result sets. In the result set of a main query, for example, column names do not have to be unique, and a system-generated name like 'SUM(E.SALARY)" is acceptable.
Actually the book hasnt specfied the need for an alias at this place ...so i wanted to know why am getting this error ..I can't see which book you're reading. Post a quote. If the book is available on line, post a link, too.
create or replace view dept_sal as
select d.department_name,sum(e.salary) as d_sal
from departments d left outer join employees e
on d.department_id= e.department_id
group by d.department_name;
view DEPT_SAL created.That's the right way to do it.
Also i wanted to know if i can start a thread each time i want have a problem or can i add my questions to somebody
else's thread ..It's better to start your own thread.