Thanks for your feedback.

The 'renewal' month represents the anniversary month and is collected from multiple sources and this routine (MaxVariance and EarliestMonth) is part of a larger process used to...

Sorry was rushing to get the sample over to you, thank you for tidying it up.

I've left the EarliestMonth value Null for records where the MaxVariance is > 2. ...

DECLARE @Sample

TABLE (

PersonID int,

Month char(01)

...

Right sorry Paul, don't shout at me :), I've managed to grab the person who has this business requirement and dug a little deeper.

The idea is to find the earliest...

For PersonID 3 the earliest month value would be '01'

I'm sorry Paul and really do appreciate your help. When you're so close to a problem sometimes it's hard to verbalise all the intricacies. If you can help...

Sorry, unfortunately the month value is an anniversary/renewal month therefore is non year specific. So the wrap affect only comes into play when December(12) is in the list.

Sorry, to add to the issue.

I also need to know the max variance between the values for each PersonID i.e the max variance between '01','02','03' is 2 and given '11','12','01'...

p.s. not on the fly but as a default for each new source

Thank you Mark, but unfortunately even with this change the same result is occuring 🙁