I tried to calculate difference between rows in a field using a query:
Illustrations: input:year,month,fixes output:increase year | month | fixes | increase ------+-------+----------+----------- 2006 | 04 | 1 | 0 2006 | 05 | 4 | 3 2006 | 06 | 3 | -1
Increase column as output by difference between adjacent rows in fixes.
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