Question

I have a table with an skey column (generated by a sequence number) and a timestamp column.

I need to write a query that will find any records with a higher skey but an older timestamp than preceding records as it will indicate an issue.

ie something along the lines of:

select * from table
where timestamp < (select max(timestamp) from table where skey less than currrecord)
order by skey desc;

Answer 1

Use a self join i.e. join the table to itself with the criteria that you have mentioned (SKey and TimeStamp)

Select T1.Skey HigherSkey, T2.SKey LowerSkey, T1.Timestamp LowerTimestamp, T2.Timestamp HigherTimestamp
From MyTable T1
Inner Join MyTable T2
    On T1.Timestamp < T2.Timestamp
    And T1.Skey > T2.Skey