How to clear a postgresql table column?

Question

PostgreSQL

Is there an analogue of the truncate table command to clear a specific column/column in a table?

Answer 1

What does "clear column" mean? Removing all values ​​in it? Removing a column from a table?
ALTER TABLE "table" DROP COLUMN "column"

Answer 2

How do you imagine that? truncate throws out files and allocates empty ones. And for the column? This is not a columnar DBMS.
You can do this:

begin;
alter table tablename drop column foo;
alter table tablename add column foo ...
commit;

You can create a table through create table as select and then replace the old one with a new one.