See the cqlsh script below. If you comment out the "c1" line then the "copy to" command exports 0 rows even though the "select *" works fine!
ian@ian: cqlsh --version
cqlsh 2.2.0
ian@ian: nodetool -h localhost version
ReleaseVersion: 1.1.9
USE test_keyspace;
DROP TABLE foo;
CREATE TABLE foo (
id varchar PRIMARY KEY,
a0 varchar,
a1 varchar,
a2 varchar,
a3 varchar,
a4 varchar,
a5 varchar,
a6 varchar,
a7 varchar,
a8 varchar,
a9 varchar,
b0 varchar,
b1 varchar,
b2 varchar,
b3 varchar,
b4 varchar,
b5 varchar,
b6 varchar,
b7 varchar,
b8 varchar,
b9 varchar,
c0 varchar,
-- c1 varchar, -- uncomment this line and the "copy" will fail even though the "select" works fine!
);
insert into foo (id, a1) values ('foo', 'grum');
select * from foo;
copy foo to '/tmp/foo.csv';