Use psql's \copy for a multi-line query - postgresql

Question

This is a follow-up question from this answer for "Save PL/pgSQL output from PostgreSQL to a CSV file".
I need to write a client-side CSV file using psql's \copy command. A one liner works:
db=> \copy (select 1 AS foo) to 'bar.csv' csv header
COPY 1
However, I have long queries that span several lines. I don't need to show the query, as I can't seem to extend this past one line without a parse error:
db=> \copy (
\copy: parse error at end of line
db=> \copy ( \\
\copy: parse error at end of line
db=> \copy ("
\copy: parse error at end of line
db=> \copy "(
\copy: parse error at end of line
db=> \copy \\
\copy: parse error at end of line
Is it possible to use \copy with a query that spans multiple lines? I'm using psql on Windows.

Answer 1

The working solution I have right now is to create a temporary view, which can be declared over multiple lines, then select from it in the \copy command, which fits comfortably on one line.
db=> CREATE TEMP VIEW v1 AS
db-> SELECT i
db-> FROM generate_series(1, 2) AS i;
CREATE VIEW
db=> \cd /path/to/a/really/deep/directory/structure/on/client
db=> \copy (SELECT * FROM v1) TO 'out.csv' csv header
COPY 2
db=> DROP VIEW v1;
DROP VIEW

Answer 2

We may use HEREDOC to feed multiline SQL to psql and use
# Putting the SQL using a HEREDOC
tr '\n' ' ' << SQL| \psql mydatabase
\COPY (
SELECT
provider_id,
provider_name,
...
) TO './out.tsv' WITH( DELIMITER E'\t', NULL '', )
SQL
Source: https://minhajuddin.com/2017/05/18/how-to-pass-a-multi-line-copy-sql-to-psql/

Answer 3

You can combine the server side COPY command with the \g psql command to produce a multi-line query to local file:
db=# COPY (
SELECT department, count(*) AS employees
FROM emp
WHERE role = 'dba'
GROUP BY department
ORDER BY employees
) TO STDOUT WITH CSV HEADER \g department_dbas.csv
COPY 5
I describe this technique in detial here https://hakibenita.com/postgresql-unknown-features#use-copy-with-multi-line-sql