PostgreSQL next value of the sequences?

Question

I am using PostgreSQL for my Codeigniter website. I am using grocery crud for add, edit and delete operations. While doing an edit or add, I want to rename an uploaded file

Answer 1

To answer your question literally, here's how to get the next value of a sequence without incrementing it:

SELECT
 CASE WHEN is_called THEN
   last_value + 1
 ELSE
   last_value
 END
FROM sequence_name

Obviously, it is not a good idea to use this code in practice. There is no guarantee that the next row will really have this ID. However, for debugging purposes it might be interesting to know the value of a sequence without incrementing it, and this is how you can do it.