Alias Names and Two Table Query Problems

I'm quite new to querying databases, I've only been doing it for about 2 weeks in the current job that I'm in and have never touched SQL prior to this. I'm working on trying to use alias names to pull two different sets of tables and display the fields in each table, all while ordering them by a specific field. Here is the code I'm currently trying to use when to do that: SELECT ars.facility_id, ars.service_code, ars.coding_system, ars.result_label_seq, ars.display_seq, ats.facility_id, ats.service_code, ats.coding_system, ats.display_name, ats.test_name FROM anc_test_codes AS ats, anc_results_seqs AS ars WHERE ats.service_code = ars.service_code AND ars.coding_system = ats.coding_system AND ars.facility_id = ats.facility_id AND ats.facility_id = 'C' AND ats.service_code = 'CBC' ORDER BY ats.display_name I'm sure my methods and style is totally hideous, so excuse this. The error I'm getting is a generic Oracle SQL error: SQL Command Not Properly Ended - ORA-00933 Can anyone tell me what I'm doing wrong? Any help on this would be greatly appreciated. Thanks!