升级时，系统出现“违反了UNQIUE K

A、删除invoice表单的uq_invoice约束 B、select * from invoice where code in (select invoiceid from invoice group by code having count(*)>1) order by code /*通过该查询语句，可查找是否存在相同的销售开单单号*/ C、delete from invoice where referbillid is null and refercount14 and invoiceid=‘上述B