このクエリが無効なのはなぜですか？vt_exam_details.SRV_IDの代わりにSRV_IDだけを書くと、すべてがうまく機能します
cl_id
, cl_name_last as CUSTOMER
, vt_animals.an_type
, vt_exam_details.SRV_ID
, vt_services.srv_desc
, vt_exam_details.ex_fee
from vt_clients
join vt_animals using (cl_id)
join vt_exam_headers using (an_id)
join vt_exam_details using (ex_id)
join vt_services using (srv_id)
エラー：
Error at Command Line:5 Column:3
Error report:
SQL Error: ORA-00904: "VT_EXAM_DETAILS"."SRV_ID": invalid identifier
00904. 00000 - "%s: invalid identifier"
*Cause:
*Action:
ありがとう。