PostgreSQL: Valid variable names for functions

Question

I cannot find any definitive information on what constitutes a valid variable name in a PostgreSQL function.

I am assuming the function is written using plpgsql. I know I can use letters, numerals (apart from the first character) and underscores. Is there anything else?

Where is this documented?

Answer 1

This is implicitly stated in the introduction to PL/pgSQL.

Identifiers are implicitly converted to lower case unless double-quoted, just as they are in ordinary SQL commands.

So a PL/pgSQL variable has to comply with the rules for SQL identifiers

• Manngo: Thanks for the references. I have found that I can use the $ character. I am exploring whether to affix the $ to my variables to more reliably distinguish them from column names.
• user1822: @Manngo: the common convention is to use a prefix like l_ for (local) variables and p_ for parameters passed to functions to distinguish them from column names.