BEGIN;

CREATE TABLE tbl1 (pk int primary key, c1 varchar(100), c2 varchar(250));

COPY tbl1 FROM STDIN (FORMAT CSV, HEADER TRUE);
pk,c1,c2
1,green,
2,"blue","a
q
u
a"
3,"brown",
4,"NULL",NULL
5,"?",""
6,"foo
\\.
bar","baz"
7,  ,' '
8," ",""
9,,''
\.

COMMIT;
