How use input parameter as path to COPY in function?
I am missing something basic. How can I use an input parameter as the
destination path in a COPY statement in a function. The following fails
with a syntax error at or near the parameter.
CREATE OR REPLACE FUNCTION dvd.export_tables(IN export_path text)
RETURNS void
AS
$$
BEGIN
copy dvd.genre to export_path
with
delimiter as E'\t'
null as '';
END;
$$
LANGUAGE 'plpgsql' VOLATILE
Bill Todd <pg@dbginc.com> writes:
I am missing something basic. How can I use an input parameter as the
destination path in a COPY statement in a function.
plpgsql can only substitute parameter values into places where a data
value is called for in a DML statement (ie, SELECT/INSERT/UPDATE/DELETE).
To use a parameter in other contexts, such as a utility statement like
COPY, you need to construct the command as a string and EXECUTE it.
Try something like
EXECUTE 'copy dvd.genre to ' || quote_literal(export_path) ||
$q$
with
delimiter as E'\t'
null as ''
$q$ ;
(There's any number of ways to do the quoting here, of course,
but I do strongly recommend using quote_literal() on the parameter.)
regards, tom lane
Thanks Tom. As usual, I learned a lot more from your reply than just the
answer to my question .
Bill
Tom Lane wrote:
Show quoted text
Bill Todd <pg@dbginc.com> writes:
I am missing something basic. How can I use an input parameter as the
destination path in a COPY statement in a function.plpgsql can only substitute parameter values into places where a data
value is called for in a DML statement (ie, SELECT/INSERT/UPDATE/DELETE).
To use a parameter in other contexts, such as a utility statement like
COPY, you need to construct the command as a string and EXECUTE it.
Try something likeEXECUTE 'copy dvd.genre to ' || quote_literal(export_path) ||
$q$
with
delimiter as E'\t'
null as ''
$q$ ;(There's any number of ways to do the quoting here, of course,
but I do strongly recommend using quote_literal() on the parameter.)regards, tom lane