1

SQL greenhorn alarm:
I have a table with timestamp information (44 rows) and I now would like to calculate and extract the delta between any two consecutive rows. How can I do this? I select my data with a query like:

SELECT * from "table" where "RecognitionTimestamp" >= '2018-10-03 00:00:00' and "RecognitionTimestamp" <= '2018-10-04 9:00:00'

I'm using pgAdmin4 to submit the query and look at the data.

2

You can use Windows Functions which provides calculation across a set of table rows that are somehow related to the current row. The list of functions are in General-Purpose Window Functions section of the documentation and The lead() and lag() functions are answer of your question. Your query will should like this;

SELECT *,
  "RecognitionTimestamp" - lag("RecognitionTimestamp") OVER(ORDER BY "RecognitionTimestamp") AS delta_previous,
  lead("RecognitionTimestamp") OVER(ORDER BY "RecognitionTimestamp") - "RecognitionTimestamp" AS delta_next
FROM "table" 
WHERE
  "RecognitionTimestamp" >= '2018-10-03 00:00:00' AND 
  "RecognitionTimestamp" <= '2018-10-04 9:00:00'

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