oracle database - Why is this query showing error ORA-00923:

ora 923The ORA-00923: FROM keyword not found where expected error occurs when the FROM keyword is missing, misspelled, or misplaced in the Oracle SQL statement such as select orSQL Error: ORA-00923: FROM keyword not found where expected. Can anyone tell me where I'm going wrong with this? you don't need the WITHIN GROUP clause. it's ok