SQL and PL/pgSQL Programming Style Guide

Style guidelines for SQL and in general

File names in lowercase_with_underscores, use UTF-8 encoding
Use Free Online version of the PostgreSQL SQL syntax beautifier pgFormatter
Indent with 4 spaces (don't use tabs)
Max line-length 80 characters (especially in comments)
IMPORTANT: Put keywords, datatypes and functions all-lowercase - opposite e.g. to Joe Celko’s - because they are _not_ the main content!
Else follow Sqlstyle.guide which is compatible with Joe Celko’s SQL Programming Style book

Same as above plus (inspired partially by PEP 8):
Naming conventions:
- Function names in lowercase_with_underscores (handle ST_-functions insensitive).
- Function parameter names in lowercase_with_underscores
- All-uppercase for CONSTANT_VARIABLES
- Local variables and functions start with _underscore (=> tbd.)
Whitespace and newlines:
- Two blank lines before top-level functions
- Use blank lines sparingly
- Spaces around = for assignment and in mathematical operators
- No spaces around = for default parameter values
- Multiple statements on the same line are discouraged
Comments:
- Use inline comments sparingly & avoid obvious comments
- Write in whole sentence and in plain and easy-to-follow English
- Add space after line comment (- a comment); no space for commented-out code (-raise notice)
- Keep comments up to date - incorrect comments are worse than no comments
- All "public" functions should have docstrings (""")
- In docstrings, list each argument on a separate line
- Docstrings should have a blank line after first line and before the final """

Add COMMENT ON FUNCTION: see e.g. https://github.com/pgRouting/pgrouting/blob/master/sql/withPoints/withPoints.sql
Do Unit Testing with PGUnit: https://github.com/adrianandrei-ca/pgunit (minimal introduction from Prof. Keller available).
Prefer triggers over rules.

Book "PostgreSQL Server Programming", Packt Publishing.
"Introduction to PL/pgSQL Development", by Jim Mlodgenski from AWS, given at Percona Conference 2019: https://www.percona.com/live/19/sites/default/files/slides/Introduction%20to%20PL_pgSQL%20Development%20-%20FileId%20-%20187790.pdf1.

General: