hi,
i have two tables
employees with department_id, salary...
departments with department_id, department_name...

and i want to get result as with
SELECT department_id, MIN(salary), MAX(salary), ROUND(AVG(salary),2), SUM(salary), COUNT(*)
FROM employees
GROUP BY department_id;

but with column department_name

i tried this, but it has error inside
SELECT department_id, department_name, MIN(salary), MAX(salary), ROUND(AVG(salary),2), SUM(salary), COUNT(*)
FROM employees, departments
WHERE employees.department_id=deparments.department_id
GROUP BY department_id;

any idea how to fix?
thanks

Select count through tables
are you two taking the same class?

I suggest working together to prevent double postings.

thx, but it still dont work (Error code 918, SQL state 42000: ORA-00918: column ambiguously defined)
dont you have mistake inside?

and no... we dont take same class, i dont know him and i dont understand what is common in our problems..

ORA-00918 column ambiguously defined

Cause: A column name used in a join exists in more than one table and is thus referenced ambiguously. In a join, any column name that occurs in more than one of the tables must be prefixed by its table name when referenced. The column should be referenced as TABLE.COLUMN or TABLE_ALIAS.COLUMN. For example, if tables EMP and DEPT are being joined and both contain the column DEPTNO, then all references to DEPTNO should be prefixed with the table name, as in EMP.DEPTNO or E.DEPTNO.

Action: Prefix references to column names that exist in multiple tables with either the table name or a table alias and a period (.), as in the examples above.

ok, i tried apply fix by some example on web, but still same error

SELECT department_id, d.department_name, MIN(salary), MAX(salary), ROUND(AVG(salary),2), SUM(salary), COUNT(salary)
FROM employees e, departments d
WHERE e.department_id = d.department_id
GROUP BY department_id, department_name;

pls, correct me if you know where i have mistake

Precede ALL column names with table aliases. Always. Even if you write a query on a single table. Take it as a best practice.

oh thx, that is advice i was looking for

so this is right:

SELECT e.department_id, d.department_name, MIN(e.salary), MAX(e.salary), ROUND(AVG(e.salary),2), SUM(e.salary), COUNT(e.salary)
FROM employees e, departments d
WHERE e.department_id = d.department_id
GROUP BY e.department_id, d.department_name;

its working!!!!