ORA-00934 group function is not allowed here

ORA-00934 group function is not allowed here is one of the common messages we often get while aggregating data.

Causes of ORA-00934 group function is not allowed here

This error happens when you are trying to use the where clause to restrict groups

CREATE TABLE "EMP_DATA"
( "EMP_NO" NUMBER(4,0),
"EMP_NAME" VARCHAR2(10),
"JOB" VARCHAR2(9),
"MGR" NUMBER(4,0),
"HIREDATE" DATE,
"SALARY" NUMBER(7,2),
"COMM" NUMBER(7,2),
"DEPT_NO" NUMBER(2,0)
);
insert into emp_data values( 1000, 'BILL', 'MANAGER', 7839, to_date('1-5-2007','dd-mm-yyyy'), 2850, null, 10 );
insert into emp_data values( 1001, 'MATT', 'MANAGER', 7839, to_date('9-6-2008','dd-mm-yyyy'), 2450, null, 10 );
insert into emp_data values( 1002, 'SCOTT', 'ANALYST', 7566, to_date('9-6-2012','dd-mm-yyyy'), 3000, null, 20 );
insert into emp_data values( 1003, 'ARNOLD', 'ANALYST', 7566, to_date('9-6-2017','dd-mm-yyyy'), 3000, null, 20 );
insert into emp_data values( 1004, 'BANNER', 'ANALYST', 7567, to_date('9-7-2017','dd-mm-yyyy'), 4000, null, 20 );
insert into emp_data values( 1005, 'TOM', 'ANALYST', 7567, to_date('9-7-2017','dd-mm-yyyy'), 4000, null, 30 );
commit;

select dept_no,avg(salary) from emp_data where avg(salary) > 1000 group by dept_no;

select dept_no,avg(salary) from emp_data where avg(salary) > 1000;
              *
Error at line 1
ORA-00934: group function is not allowed here

Checklist to run to resolve the ORA-00934 group function is not allowed here

This error happens when you are trying to use the where clause to restrict groups. The right way to restrict groups is by Having clause. So the correct query is

select dept_no,avg(salary) from emp_data  having avg(salary) > 1000 group by dept_no;

Let’s see some more examples

(1) select dept_no, count(*) from emp_data where count(*) > 1 group by dept_no;
Error at line 1
ORA-00934: group function is not allowed here.

The correct way is
select dept_no, count(*) from emp_data having count(*) > 1 group by dept_no;

(2)select emp_no,salary from emp_data where salary=max(salary);
Error at line 1 
ORA-00934: group function is not allowed here.

The correct way is
select emp_no,salary from emp_data where salary=(select max(salary) from emp_data);

I hope you like these simple tips on ORA-00934 group function is not allowed here

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