SQL之rank()、dense_rank()、row_number()的差异
rank() dense_rank() row_number() with xx as (select '1' testid, 'A1' testname, '20090520' creat_time from dual union all...
rank() dense_rank() row_number() with xx as (select '1' testid, 'A1' testname, '20090520' creat_time from dual union all...