FTP

Plain FTP is read by URL, ftp://[user[:password]@]host[:port]/path. Public data is still published this way, and anonymous login is the default:

SELECT * FROM 'ftp://ftp.example.org/dados/2026/arquivo.csv' WITH (delimiter = ';', encoding = 'latin1');
SELECT * FROM 'ftp://ftp.example.org/dados/pacote.zip :: tabela.csv';
SELECT * FROM 'ftp://ftp.example.org/dados/mensal/';       -- every file under the folder

A server that needs a login can be named once with a connection, whose paths are then ftp://name/path:

CREATE CONNECTION parceiro TYPE ftp OPTIONS (host = 'ftp.example.org');  -- PARCEIRO_USER / PARCEIRO_PASS
SELECT * FROM 'ftp://parceiro/saida/2026-10.csv';

Options are host port user password; user/password follow the NAME_USER/NAME_PASS convention, and without them the login is anonymous. Without a connection the login is the URL’s, else FTP_USER / FTP_PASSWORD from the environment, else anonymous. A name with spaces or accents is percent-encoded in the URL (arquivo%20um.csv). A connection name is process-wide, as an SFTP one is.

FTP has no cheap random access, so each file is downloaded whole to a temporary folder the first time a run reads it and read from there. Every format works, zip members, Parquet and Excel included, and a CSV still splits across -j lanes. A second read of the same URL in the run uses the copy, and the copies are removed when the run ends; error messages name the URL, not the copy.

A trailing / reads a folder: every file under it, subfolders included, with names starting _ or . skipped, as for any folder read. Folders are listed by MLSD, or by NLST and a CWD to each name on servers without it. A folder of more than 10,000 files is refused rather than copied, so a URL one level too high fails fast: read a subfolder or a file instead.

Transfers are binary over a passive data connection (EPSV, or PASV where the server refuses it). The address a PASV reply advertises is ignored in favour of the server’s own host, as a server behind NAT often advertises a private one. Plain FTP sends the password in clear text, and FTPS (FTP over TLS) is not supported; use SFTP for anything private.

A busy server (a 4xx reply) or a dropped connection fails the run as transient (exit 75), worth retrying; a missing file (550) or a refused login fails it for good, with the server’s reply in the message. FTP is read only: LOAD INTO 'ftp://…' is refused by check.