Delete duplicate records in a datasheet

Data | repeat | Duplicate record delete a traffic violation data table duplicate record (same time [haptime], vehicle number number [numberplate], the punishment reason [reason])
First, the principle of the method:
1. In Oracle, each record has a rowid,rowid that is unique across the database, ROWID determines which data files, blocks, and rows are in Oracle for each record.
2. In duplicate records, all columns may have the same content, but ROWID will not be the same, so just make sure that those with the largest rowid in the duplicate record are OK, and all the rest is deleted.

Second, the realization method:
1, query duplicate records
Select Rowid,haptime,numberplate,reason from Peccancy
--delete from Peccancy6 Peccancy6
where Peccancy.rowid!=
(
Select Max (ROWID) from Peccancy b
where peccancy.haptime = B.haptime and
Peccancy.numberplate = B.numberplate and
Peccancy.reason = B.reason
)


2. Delete duplicate records
Delete from Peccancy peccancy
where Peccancy.rowid!=
(
Select Max (ROWID) from Peccancy b
where peccancy.haptime = B.haptime and
Peccancy.numberplate = B.numberplate and
Peccancy.reason = B.reason
)