query to return previous date

[Erick]

I have a table with a date field (dates when file had been backed up). The backing up of files doesn't happen everyday so there will be gaps in the date sequence.

what I need is to write a query to return for every entry (row), the previous back up date.

any idea how this can be done?

 

[Norie]

Erick

I think gaj104 has posted the SQL to do it in one query rather than my idea of using 2.

Mind you I'm still not 100% sure what you are looking for.

Your data seems to be producing the previous date for every entry.

Perhaps I was wrong but I thought you wanted the previous date for each machine, ie one date per machine.

 

[Erick]

Erick

I think gaj104 has posted the SQL to do it in one query rather than my idea of using 2.

Mind you I'm still not 100% sure what you are looking for.

Your data seems to be producing the previous date for every entry.

Perhaps I was wrong but I thought you wanted the previous date for each machine, ie one date per machine.

Hello Norie, I haven't actually tried gaj104's sql but you are right. I need the previous date for each machine. If you look at the sample excel table i posted, the date for the 16th returns the 14th (not 15th) because this is the previous date for MC1.