Canonical way to map null->false

Question

What is a canonical expression for the following:

NULL  -> false
false -> false
true  -> true

What I am using is:

select (foo is not null and foo)

which seems to work fine, but I'm wondering if there is a standard convention for this.

Answer 1

select coalesce(foo, false) from table

Answer 2

I just looked it up. COALESCE() is ansi SQL. So SELECT (foo, false) would give foo or false.