Postgres import file that has columns separated by new lines - mysql

Question

I have a large text file that has one column per row and I want to import this data file into Postgres.
I have a working MySQL script.
LOAD DATA LOCAL
INFILE '/Users/Farmor/data.sql'
INTO TABLE tablename
COLUMNS TERMINATED BY '\n';
How can I translate this into Postgres? I've tried amongst other this command.
COPY tablename
FROM '/Users/Farmor/data.sql'
WITH DELIMITER '\n'
However it complains:
ERROR: COPY delimiter must be a single one-byte character

Answer 1

The immediate error is because \n is just a two char string, \ and n.
You want:
COPY tablename
FROM '/Users/Farmor/data.sql'
WITH DELIMITER E'\n'
The E'' syntax is a PostgreSQL extension.
It still won't work, though, because PostgreSQL's COPY can't understand files with newline column delimiters. I've never even seen that format.
You'll need to load it using another tool and transform the CSV. Use an office suite, the csv module for Python, Text::CSV for Perl, or whatever. Then feed the cleaned up CSV into PostgreSQL.

Answer 2

While postgresql will not recognize \n as a field delimiter, the original question asked how to import a row as a single column and this can be accomplished in postgresql by defining a delimiter not found in the data string. For example:
COPY tablename
FROM '/Users/Farmor/data.sql'
WITH DELIMITER '~';
If no ~ is found in the row, postgresql will treat the entire row as one column.

Answer 3

Your delimiter is two characters so it's a valid error message.
I believe the simplest approach would be to modify the file you're importing from and actually change the delimiters to something other than \n but that might not be an option in your situation.
This question addresses the same issue:
ERROR: COPY delimiter must be a single one-byte character