Hi, >> So, my question is: Is there a recognised technique (using SQL only, >> not PL/pgSQL - soutions based on the latter are easy to find) whereby >> I can do a basic Linear Interpolation? > I don't have a recognized technique, nor care to ponder one right now, but what you've described would best be done in pure SQL using WITH RECURSIVE, which provides an iterative approach to SQL result building. Which is more commonly done in a procedural language. The algorithm you describe is an iterative algorithm and so I'm wondering why place the arbitrary restriction on using pure SQL when it likely wouldn't provide a very readable nor performant solution relative to a procedural (pl/pgsql or otherwise) one? Well, it would be trivial to do something with PL/pgSQL (just Google and download the code - there are a few examples around). I''m a big fan of this site https://explainextended.com/ - this guy can do anything with SQL - I'd like to try and learn how to do the same. You're idea of RECURSIVE is exactly along the lines I was thinking of - I'll persevere and see what I can come up with using WITH RECURSIVE - I've use it before. Thanks for your input and rgs, Pól... > David J.
