Konstantin Izmailov <pgfizm@gmail.com> writes:
> you know that some Postgres functions are listed in pg_proc while others are
> not. For example, all Data Type Formatting function are in pg_proc (to_char,
> to_hex, ...). While several of the Date/Time Functions are not there
> (extract, localtime, ...).
The ones that appear not to be there are ones that the SQL standard
demands special weird syntax for. The grammar translates such calls
to standard function calls to underlying functions, which usually are
named a bit differently to avoid confusion. For instance
extract(field from some_expr) becomes date_part('field', some_expr).
If you want to know what all of these are, see the func_expr production
in parser/gram.y.
> This causes issues to Windows integration as well.
Complain to the SQL standards committee, especially to those members
who seem to think COBOL represented the apex of programming language
syntax design :-(
regards, tom lane