mysql迁移GBase 8t的一个问题咨询

select count(t.serialno)  FROM ( SELECT tRe.serialno,tOrg.orgname,tRe.sortnum,tRe.date_input,tOrd.admis_serialno,tRe.serialno_no,tPa.patientid,tPa.patient_name,tPa.patient_sexId,tPa.birth_date,tPa.patient_identityname FROM t_pa_register tRe LEFT JOIN t_patient tPa on tRe.patientid = tPa.patientid LEFT JOIN t_ord tOrd on tRe.serialno = tOrd.serialno JOIN t_org tOrg ON tRe.orgid=tOrg.orgid where tPa.orgid_hosp = 'demo'  AND tRe.admission_statue = '01' AND tRe.serialno  ''  AND tRe.serialno IS NOT NULL AND tOrd.date_canc is null AND tOrd.empid_canc IS NULL AND tOrd.rek_status = 1 AND tOrd.ord_date BETWEEN '2016-05-18 00:00:00' AND '2016-05-18 23:59:59' GROUP BY tRe.serialno ) t
在GBase 8t中执行报错，请问是什么原因？