FROM keyword not found where expected (Oracle) ORA-00923

ora 923I have been getting the error ORA-00923: FROM keyword not found where expected and do not know why, please help. Do check for missing spaces in the sql query. I ran into anotherORA-00923: FROM keyword not found where expected Below is the SQL : SELECT A.Agent_key, Sum(Total_Orders) FROM (SELECT A.Agent_key, Sum(Total_Orders)