Hello,

Please look at the following example, where we measure the size of
some kids:

SELECT name, measurement_date, size FROM kids WHERE name = 'Bill'
ORDER BY 1,2;

Bill | 2007-01-01 | 90
Bill | 2007-05-01 | 95
Bill | 2007-12-01 | 101

How can I rewrite the query that it gives me the growth since the last
measurement? Like this:

Bill | 2007-01-01 | 90 | (null)
Bill | 2007-05-01 | 95 | 5
Bill | 2007-12-01 | 101 | 6

There are surely many ways to do this, but what is the best / easiest
approach?

Thanks and best,

Hans

"Hans Mayr" <mayr1972 (AT) gmx (DOT) de> a écrit dans le message de news: 37711712-b230-49de-a976-ff092b0adc68...oglegroups.com...
Using LAG function.

Regards
Michel

Thank you!