ORA-00933: SQL command not properly ended

Update sms_Mo_Port_Log
Set usertime = Trunc(Sysdate-1) + (13*60+35) /(24*60)
From sms_sendmsg_ago a,sms_Mo_Port_Log b
Where a.msgid_db=b.msgid And a.usertime = Trunc(Sysdate-1);

报这样的错误:
ORA-00933: SQL command not properly ended


------解决方法--------------------------------------------------------
Update sms_Mo_Port_Log b
Set b.usertime = Trunc(Sysdate-1) + (13*60+35) /(24*60)
Where exists (select 'X ' from sms_sendmsg_ago a
where a.msgid_db=b.msgid
And a.usertime = Trunc(Sysdate-1));