select t.*
from (select a.*, row_number() over(PARTITION BY A.IDENTITYCARD order by A.ACCESSIONTIME desc) rn
from T_PATIENT_INFO a) t
where t.rn = 1
T_PATIENT_INFO--表
IDENTITYCARD--证件号码
ACCESSIONTIME--更新时间
select t.*
from (select a.*, row_number() over(PARTITION BY A.IDENTITYCARD order by A.ACCESSIONTIME desc) rn
from T_PATIENT_INFO a) t
where t.rn = 1
T_PATIENT_INFO--表
IDENTITYCARD--证件号码
ACCESSIONTIME--更新时间