psycopg2.ProgrammingError: syntax error at or near "\"

Question

I have a python module which copy data from a table to a file.Im using postgresql as database server. COPY is the command is to be used to do the above action.

However in a blog (http://grokbase.com/t/postgresql/pgsql-general/058tagtped/about-error-must-be-superuser-to-copy-to-or-from-a-file) it states that, You can use \copy in 'psql' on the client side, but you have to be a superuser to do COPY on the server side, for security reasons. So I used \copy command. When I try to execute the below method, it results in error as

psycopg2.ProgrammingError: syntax error at or near "\" LINE 1: \copy

I can't find why its throwing error. can someone help me out?

def process():
     query="\copy %s TO %s"%('test_table', 'test_file.txt')

     @env.with_transaction()
     def do_execute(db):
         cursor = db.cursor()
         cursor.execute(query)

do_execute is a database wrapper, which creates connection and executes the query.

\copy is a command only recognized by the psql command line tool. It is not valid SQL. The command line tool most likely implements the command using several SQL constructs to load data then export it to a text file. — Martijn Pieters
And for that valid SQL - you can find it at postgresql.org/docs/8.2/static/sql-copy.html — Jon Clements
The same page states: If you are not using 'psql' and your client library supports it, you can use 'COPY FROM stdin' and pass the data across the client connection. — Martijn Pieters
possible duplicate of Can not "COPY FROM" with Postgres & Python — Martijn Pieters

Craig Ringer Craig Ringer · Accepted Answer · 2013-08-08T13:38:43

\ is an escape in Python strings, so your string contains the escape \c. However \c is an invalid escape in Python, and Python leaves invalid escapes unchanged, so "\copy" is just \copy. (Thus @tiziano's answer is misleading).

>>> print "\c"
\c

The real problem is that \copy is a psql command, not a server side PostgreSQL command. You can't use it with a client other than psql. You must instead use the psycopg2 support for COPY to do it via your client driver.

psycopg2.ProgrammingError: syntax error at or near "\"

1 Answers