What I'm trying to do is something I've not done before (perhaps this is why!), say you've created a temp table - a bit like my example - but you wanted to count how many times an item appeared in it over specific date ranges...

I was thinking I could join to the table once to get 'all time'

then join again and have something along the lines of and Log_Date > dateadd(mm, -6, getdate()) to essentially perform the count on a subset and so on.

In the past I'd used separate temp tables based on the time horizons, so say 4 temp tables rather than attempting 4 joins, or I'd done a union.

I think the approach I'm tyring to adopt basically isn't going to work - I blame it on an office that's far too warm - can't think straight! (well that's my excuse and I'm sticking to it)

The arithmetic overflow makes sense now though I guess because the actual temp table has 659,965 rows so yeah the square of that is quite large!