basically first we're writing a query that selects the actual value, as it is and as the second field, we dynamically create the field by subtracting it by 1 and running abs() on it.

So now we have a temp table in memory.

when you wrap that query with from( ... ), you're querying this transient table as if it was real so now you have both the original value and the adjusted value for sorting so you sort on the adjusted value and since both field are on the same row, properly sorts the unchanged value.

Think of it as piping (ie: echo 'yes this is true' | wc -c )

That's when i realized what was going on, sub-queries on sub-queries is just like starting with data and piping it to another command that makes minor changes