The following bug has been logged on the website:
Bug reference: 17450
Logged by: Suman Ganguly
Email address: ganguly.04@gmail.com
PostgreSQL version: 10.17
Operating system: x86_64-pc-linux-gnu
Description:
select substring('123456', 0 , 5)
On running this, Postgres returns '1234'
Expecting '12345' to be returned as per the documentation