SQL

psql fatal database does not exist

# So you do not have to create a database with your role name

psql -U Username DatabaseName 

fatal database postgres does not exist

psql -d template1

psql: error: FATAL: database "odoo" does not exist

# if your database is different as your login name you must add the database name
psql -U Username DatabaseName 

psql database does not exist

It appears that your package manager failed to create the database named $user for you. The reason that

psql -d template1
works for you is that template1 is a database created by postgres itself, and is present on all installations. You are apparently able to log in to template1, so you must have some rights assigned to you by the database. Try this at a shell prompt:

createdb
and then see if you can log in again with

psql -h localhost

fatal database postgres does not exist

If the field is already a string, this will work

 SELECT RIGHT('000'+ISNULL(field,''),3)
If you want nulls to show as '000'

It might be an integer -- then you would want

 SELECT RIGHT('000'+CAST(field AS VARCHAR(3)),3)