How to pass a multi line copy sql to psql

I have been working with a lot of ETL stuff lately and have to import/export data from our postgresql database frequently.

While writing a script recently, I found that psql doesn’t allow using the \COPY directive with a multi line SQL when it is passed to the psql command. The only workaround seemed to be squishing the sql into a single line. However, this makes it very difficult to read and modify the SQL. This is when bash came to my rescue :)

Here is a hacky way to do use multiline SQL with \COPY.

This just strips the newlines before sending it to psql. Have your cake and eat it too :)

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# Using a file
psql -f <(tr -d '\n' < ~/s/test.sql )
# or
psql < <(tr -d '\n' < ~/s/test.sql )
# Putting the SQL using a HEREDOC
cat <<SQL | tr -d '\n' | \psql mydatabase
\COPY (
SELECT
provider_id,
provider_name,
...
) TO './out.tsv' WITH( DELIMITER E'\t', NULL '', )
SQL

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