Example: Specifying a GROUP BY Clause on Nonaggregate Expressions When the Select List Includes an Aggregate - Teradata Vantage

If you specify an aggregate in the select expression list of a query, then you must also specify a GROUP BY clause that includes all nonaggregate expressions from the select list. Otherwise, the system returns the following message.

     Selected non-aggregate values must be part of the associated group.

The system returns error message 3504 whenever an aggregate query includes a nonaggregate expression in its SELECT list, WHERE clause, ORDER BY clause, or HAVING clause, but not in a GROUP BY clause.

The system also returns this error when ORDER BY and WITH clauses specify aggregates, but the select list for the query does not.

For example, the database ends the following query, which does not specify a GROUP BY clause that groups on the only nonaggregate expression in the select list, which is department_number:

     SELECT department_number, SUM(salary_amount)
     FROM employee
     WHERE department_number IN (100, 200, 300);

To work as intended, the query must be rewritten with an appropriate GROUP BY clause:

     SELECT department_number, SUM(salary_amount)
     FROM employee
     WHERE department_number IN (100, 200, 300)
     GROUP BY department_number;

The following statement, which does not specify all nonaggregate columns from the select list in its GROUP BY clause, ends and returns an error.

     SELECT employee.dept_no, department.dept_name, AVG(salary)
     FROM employee, department
     WHERE employee.dept_no = department.dept_no
     GROUP BY employee.dept_no;

The qualified nonaggregate column department.dept_name is missing from the GROUP BY clause.

The following statement aborts and returns an error because the nonaggregate grouping column specified in the ORDER BY clause is not also specified in the GROUP BY clause.

     SELECT employee.dept_no, AVG(salary)
     FROM employee, department
     WHERE employee.dept_no = department.dept_no
     ORDER BY department.dept_name
     GROUP BY employee.dept_no;

The following statement, based on the table definitions shown, aborts and returns an error because the aggregate query includes a nonaggregate expression, d1, in its HAVING clause, but not in the GROUP BY clause.

     CREATE TABLE t1(a1 int, b1 int, c1 int, d1 int);
     CREATE TABLE t2(a2 int, b2 int, c2 int, d2 int);
     SELECT min(a1) as i, max(b1) as j from t1
     GROUP BY c1
     HAVING 30 >= (sel count(*) from t2 where t1.d1=5);

The correct form of the query includes the nonaggregate expression, d1, in its HAVING clause and in the GROUP BY clause.

     SELECT min(a1) as i, max(b1) as j from t1
     GROUP BY c1, d1
     HAVING 30 >= (sel count(*) from t2 where t1.d1=5);