正则匹配日期，提取左边10个字符，简单判断日期，并且要求大于今天，或者备注为空

$sql = "select * from reader,reader_cert where reader_cert.cert_id=reader.cert_id and reader.cert_id = :userid and (password = :password or password = :md5password) and cert_flag='1' and (regexp_substr(trim(remark),'[[:digit:]-]*',1)>to_char(sysdate,'yyyy-mm-dd') or regexp_substr(trim(remark),1) is null )";