I have a table of data that is sorted by a date field. When sorted I have another column with a number. This number must show either the same as the previous value (as sorted by date) or increment. If the number goes down, it is an error in the data entry and needs to be checked.

I need a query that will sort the data by the date column, then check this number field to make sure the numbers are either the same or incrementing. A query that will show just the offending rows is also an option. I just don't know where to start. I can sort the columns, but don't know how to make this exclusion. Please advise. Thanks

select ...
 from (
select a.*,  
       lag(num_col) over (order by dt_column) last_num,
       lead(num_col) over (order by dt_column)next_num
  from table a
)
where <whatever you want...>
order by dt_column