问为什么会出现错误00933: sql命令未正确结束？

EN

Insert into uscg_awdattachment_request columns(seq, uscgextractkey)
select tooth.seq, 1 group_num
from(
select b.seq, b.uncompressed, a.docnum, b.dockey, b.verkey, b.filename, b.storedfileblob, b.updatetimestamp, row_number() over(partition by a.dockey order by b.updatetimestamp asc) as obs_no
  from (select c.*
         from prism.supportdoc c) b 
         left join prism.header a
         on a.dockey = b.dockey and a.verkey = b.verkey) tooth
where tooth.obs_no = 1;