I'm getting the below error while running the below script. My goal is to create a function in Postgres to return 1 as a bigint. Help please!
hashtagpostgresnoobie
ERROR: function result type must be bigint because of OUT parameters
CREATE OR REPLACE FUNCTION GetNumberOne(
OUT numberone bigint)
RETURNS SETOF record AS
$BODY$
SELECT CAST(1 AS BIGINT) AS "NUMBERONE";
$BODY$
LANGUAGE sql VOLATILE;
You've suddenly encountered the feature ) Record needs two and more fields. So when you have only one out variable, then result must be scalar.
So, you can simply do what compilers ask )
CREATE OR REPLACE FUNCTION GetNumberOne(
OUT numberone bigint)
RETURNS bigint AS
$BODY$
SELECT CAST(1 AS BIGINT) AS "NUMBERONE";
$BODY$
LANGUAGE sql VOLATILE;
plpgsql example:
CREATE OR REPLACE FUNCTION NumberOne()
RETURNS bigint AS
$BODY$
DECLARE num bigint;
BEGIN
num := 1;
RETURN num;
END
$BODY$
LANGUAGE plpgsql VOLATILE;
select * from NumberOne()
Related
I have a bunch of functions that return the same table schema, so I have to repeat the same table schema over and over between those functions' declarations, to make this example simple let's say we have two functions that return the same table schema:
Table: people
CREATE TABLE people(full_name TEXT, age integer);
Functions:
CREATE OR REPLACE FUNCTION get_people_by_age(_age integer)
RETURNS TABLE(full_name TEXT, age integer)
LANGUAGE PLPGSQL
AS
$$
BEGIN
RETURN QUERY SELECT * FROM people WHERE people.age = $1;
END
$$
CREATE OR REPLACE FUNCTION get_people_by_name(_full_name text)
RETURNS TABLE(full_name TEXT, age integer)
LANGUAGE PLPGSQL
AS
$$
BEGIN
RETURN QUERY SELECT * FROM people WHERE people.full_name = $1;
END
$$
Is there a way to refer to the existing table within the function declarations? I imagine something like this:
CREATE OR REPLACE FUNCTION get_people_by_age(_age integer)
RETURNS TABLE(people)
LANGUAGE PLPGSQL
AS
$$
BEGIN
RETURN QUERY SELECT * FROM people WHERE people.age = $1;
END
$$
CREATE OR REPLACE FUNCTION get_people_by_name(_full_name text)
RETURNS TABLE(people)
LANGUAGE PLPGSQL
AS
$$
BEGIN
RETURN QUERY SELECT * FROM people WHERE people.full_name = $1;
END
$$
Where instead of declaring the same schema in every function I refer to a table that already exists, is it possible?
Use returns setof
CREATE OR REPLACE FUNCTION get_people_by_name(_full_name text)
RETURNS setof people
LANGUAGE PLPGSQL
AS
$$
BEGIN
RETURN QUERY SELECT * FROM people WHERE people.full_name = _full_name;
END
$$;
Or a bit simpler as a SQL function:
CREATE OR REPLACE FUNCTION get_people_by_name(_full_name text)
RETURNS setof people
LANGUAGE sql
AS
$$
SELECT * FROM people WHERE people.full_name = _full_name;
$$;
I have a function that delete an entry from my table. Also I need to return the id of the deleted entry.
CREATE OR REPLACE FUNCTION mydb.remove_item(item_id_param text)
RETURNS TABLE(id integer)
LANGUAGE 'plpgsql'
AS $BODY$
BEGIN
RETURN QUERY
DELETE FROM mydb.items_table
WHERE item_id = item_id_param;
END;
$BODY$
When I execute the above function, it shows error as;
ERROR: cannot open DELETE query as cursor
CONTEXT: PL/pgSQL function mydb.remove_item(text) line 6 at RETURN QUERY
What is wrong in my function?
You need to use the RETURNING clause in order to return the IDs of the deleted rows:
CREATE OR REPLACE FUNCTION mydb.remove_item(item_id_param int)
RETURNS TABLE(id integer)
LANGUAGE plpgsql
AS $BODY$
BEGIN
RETURN QUERY
DELETE FROM mydb.items_table
WHERE item_id = item_id_param
RETURNING items_table.id; --<< this
END;
$BODY$
;
You do not need plpgsql for this. A simple scalar SQL function will do.
create or replace function mydb.remove_item(item_id_param int) returns int as
$BODY$
DELETE FROM mydb.items_table
WHERE item_id = item_id_param
RETURNING items_table.id;
$BODY$
language sql;
How can I capture different columns into different variables like so (note this is only pseudocode so I am assuming it will cause errors. Example taken from here)
create or replace function get_film (
p_pattern varchar
)
returns table (
film_title varchar,
film_release_year int
)
language plpgsql
as $$
begin
return query
select
title,
release_year::integer
from
film
where
title ilike p_pattern;
end;$$
create or replace function get_film_into_variables (
p_pattern varchar
)
returns null
language plpgsql
as $$
declare
v_title varchar,
v_release_year integer
begin
SELECT
get_film (p_pattern)
INTO
v_title,
v_release_year;
end;$$
Assuming you have some purpose for the variables after retrieving them not just ending the function your "get_film_into_variables" is almost there. But first let's backup just a bit. A function that returns a table does just that, you can use the results just like a table stored on disk (it just goes away after query or calling function ends). To that end only a slight change to the "get_film_into_variables" function is required. The "get_film" becomes the object of the FROM clause. Also change the returns null, to returns void. So
create or replace function get_film_into_variables (
p_pattern varchar
)
returns void
language plpgsql
as $$
declare
v_title varchar;
v_release_year integer;
begin
select *
from get_film (p_pattern)
INTO
v_title,
v_release_year;
end;
$$;
The above works for a single row returned by a function returning table. However for a return of multiple rows you process the results of the table returning function just lake you would an actual table - with a cursor.
create or replace
function get_film_into_variables2(p_pattern varchar)
returns void
language plpgsql
as $$
declare
k_message_template constant text = 'The film "%s" was released in %s.';
v_title varchar;
v_release_year integer;
v_film_message varchar;
c_film cursor (c_pattern varchar) for
select * from get_film (c_pattern);
begin
open c_film (p_pattern);
loop
fetch c_film
into v_title
, v_release_year;
exit when not found;
v_film_message = format( k_message_template,v_title,v_release_year::text);
raise notice using
message = v_film_message;
end loop;
end;
$$;
BTW: the get_film function can be turned into a SQL function. See fiddle here. For demo purposes get_film_into_variable routines return a message.
I am working on a compatibility issue, I want to create a SQL function which can return an int or a Varchar based on the conditions in the program.
For example, I have a function named foo.
CREATE or REPLACE FUNCTION foo(param VARCHAR(100))
-- Which datatype I should use here?
RETURNS SOME_DATATYPE AS
$$
SELECT
CASE UPPER(param)
WHEN 'varchar' THEN CAST((SELECT 'varchar_value') AS varchar)
WHEN 'int' THEN CAST((SELECT 1426598) AS int)
ELSE param||' is not supported.'
END
$$
LANGUAGE SQL;
For the following queries, I am expecting output as follows.
select pg_typeof(foo('varchar')) from dual;
--I am expecting varchar as output.
select pg_typeof(foo('int')) from dual;
--I am expecting int as output.
Please suggest if such a feature is there, Or any alternative I can try to achieve the same.
The closest thing would be to overload the function:
create or replace function foo(param text)
returns text
$$
select param;
$$
language sql;
create or replace function foo(param int)
returns int
$$
select param;
$$
language sql;
create or replace function foo(param date)
returns int
$$
select param;
$$
language sql;
I would like to have this function return as an array which contains all ID (integer) from this query, but i am stuck here:
CREATE OR REPLACE FUNCTION public.all_id(
prm_id integer)
RETURNS SETOF integer
LANGUAGE 'plpgsql'
COST 100.0
AS $function$
DECLARE
all_id integer;
-- all_id integer[]; gives an error, while integer only returns last value
BEGIN
SELECT id
COLLECT INTO all_id
FROM subject_data
WHERE sab_subject = (
SELECT sab_subject
FROM subject_data
WHERE id = prm_id
);
RETURN NEXT all_id;
END;
$function$;
SELECT * FROM public.all_id(1);
here's an example of fn:
t=# create or replace function ar() returns int[] as $$
declare ia int[];
begin
select array_agg(oid::int) into ia from pg_database;
return ia;
end;
$$ language plpgsql;
CREATE FUNCTION
t=# select * from ar();
ar
-----------------------------------------------------------
{13505,16384,1,13504,16419,16816,17135,25542,25679,25723}
(1 row)
SETOF would return "table", language is not literal and thus does not require single quotes, and so on...
as a_horse_with_no_name correctly brings out, you don't need plpgsql for this. A simple query will work:
SELECT array_agg(id)
FROM subject_data
WHERE sab_subject = (
SELECT sab_subject
FROM subject_data
WHERE id = PRM_ID_VALUE
)