Mistake in Syntax definition of ALTER TABLE

PG Doc comments form <noreply@postgresql.org> writes:

I think there's a mistake under "and table_constraint is:" where the
different constraints are listed.
Here: https://www.postgresql.org/docs/current/sql-altertable.html

The definition here allows for CHECK constraints to be deferrable when they
are not.

It's not a mistake, we are simply not trying to make the syntax diagram
reflect that particular implementation restriction. I doubt that making
it do so would be an improvement: we'd have to have two kinds of
column_constraint in the diagram.

regards, tom lane