I'm trying to write a function in PL/PgSQL that have to work with a table it receives as a parameter.
I use EXECUTE..INTO..USING statements within the function definition to build dynamic queries (it's the only way I know to do this) but ... I encountered a problem with RECORD data types.
Let's consider the follow (extremely simplified) example.
-- A table with some values.
DROP TABLE IF EXISTS table1;
CREATE TABLE table1 (
code INT,
descr TEXT
);
INSERT INTO table1 VALUES ('1','a');
INSERT INTO table1 VALUES ('2','b');
-- The function code.
DROP FUNCTION IF EXISTS foo (TEXT);
CREATE FUNCTION foo (tbl_name TEXT) RETURNS VOID AS $$
DECLARE
开发者_Go百科 r RECORD;
d TEXT;
BEGIN
FOR r IN
EXECUTE 'SELECT * FROM ' || tbl_name
LOOP
--SELECT r.descr INTO d; --IT WORK
EXECUTE 'SELECT ($1)' || '.descr' INTO d USING r; --IT DOES NOT WORK
RAISE NOTICE '%', d;
END LOOP;
END;
$$ LANGUAGE plpgsql STRICT;
-- Call foo function on table1
SELECT foo('table1');
It output the following error:
ERROR: could not identify column "descr" in record data type
although the syntax I used seems valid to me. I can't use the static select (commented in the example) because I want to dinamically refer the columns names.
So..someone know what's wrong with the above code?
It's true. You cannot to use type record outside PL/pgSQL space.
RECORD value is valid only in plpgsql.
you can do
EXECUTE 'SELECT $1.descr' INTO d USING r::text::xx;
$1
should be inside the ||
,like || $1 ||
and give spaces properly then it will work.
BEGIN
EXECUTE ' delete from ' || quote_ident($1) || ' where condition ';
END;
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