Hello MBL! My goodness, that is so awesome. Thank you for assisting and showing me the `else` usage. I didn't consider it or know about it.
This now gets me the diff column correctly! The very minor thing that was aggravating was realizing I needed to do `1000000.0`, otherwise the values were 0.25 off.
```
SELECT *,
CASE
WHEN previous_transId IS NULL THEN growthpool/1000000.0-EstGrowth
ELSE (growthpool-Previous_GCOV)/1000000-EstGrowth
END AS diff
FROM
(SELECT GrowthPool,
TransactionId AS current_transId,
lag(GrowthCarry) OVER w Previous_GCOV,
GrowthCarry AS Current_GCOV,
(lag(GrowthCarry) OVER w) AS GCOVAW,
lag(TransactionId) OVER w AS previous_transId,
CASE
WHEN lag(TransactionId, 1) OVER w THEN ((TransactionId) - (lag(TransactionId) OVER w))*0.003*250
ELSE TransactionId *0.003*250
END AS EstGrowth
FROM CalculateGrowth2 WINDOW w AS (PARTITION BY PIG
ORDER BY PIG)) e
WHERE EstGrowth IS NOT NULL
```
Thank you for your help!