I'm trying to pass in a list of values into a Postgres 11 procedure. The query has an IN condition. How do I pass in a list of values to the procedure & then how do I use it in the query?
create or replace procedure some_procedure(
source_id_list character varying <-- is this correct?
)
language plpgsql
as $$
declare
result_count int;
begin
select count(*)
into result_count
from table sd
where sd.id in source_id_list <-- syntax error
;
RAISE NOTICE 'result: %', result_count;
end;
$$
IN expects a list of values, while you are giving it a string.
If you can change the datatype of the argument to the procedure, then it would be simpler to use an array:
create or replace procedure some_procedure(source_id_list int[])
language plpgsql
as $$
declare
result_count int;
begin
select count(*)
into result_count
from table sd
where id = any(source_id_list);
raise notice 'result: %', result_count;
end;
$$
If you can't change the argument of the datatype, then another option uses string_to_array() to parse the string as an array:
select count(*)
into result_count
from table sd
where sd.id = any(string_to_array(source_id_list, ',')::int[]);
Related
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 have an express.js server running an application and from that server I can access or create "variant_id"s in PostgreSQL (Version 11) by using a stored procedure.
SELECT(get_or_create_variant_id(info_about_variant));
Sometimes I also need to get a bunch of these variant ids back by using a different stored procedure that takes multiple variants and returns multiple ids.
SELECT(get_or_create_variant_ids([info_about_variant, info_about_another_variant]));
What is the best way to generalize getting/creating a single id to doing multiple at once? I'm handling it in a LOOP in my stored procedure, but it feels like I should be able to use a JOIN instead.
CREATE OR REPLACE FUNCTION get_or_create_variant_id(
variant_in VARIANT_TYPE
) RETURNS INT AS $$
DECLARE variant_id_out INTEGER;
BEGIN
-- I'll be changing this to a ON CONFLICT block shortly
SELECT(get_variant_id(variant_in) INTO variant_id_out);
IF (variant_id_out IS NOT NULL) THEN
RETURN variant_id_out;
ELSE
INSERT INTO public.variant (
[some_fields]
)
VALUES (
[some_values]
)
RETURNING variant_id INTO variant_id_out;
RETURN variant_id_out;
END IF;
END;
$$ LANGUAGE plpgsql;
-- What is the best way to avoid a loop here?
CREATE OR REPLACE FUNCTION get_or_create_variant_ids(
variants_in VARIANT_TYPE []
) RETURNS INT [] AS $$
DECLARE variant_ids_out INTEGER [];
DECLARE variants_in_length INTEGER;
DECLARE current_variant_id INTEGER;
BEGIN
SELECT (array_length(variants_in, 1) INTO variants_in_length);
FOR i IN 1..variants_in_length LOOP
SELECT(get_or_create_variant_id(variants_in[i]) INTO current_variant_id);
SELECT(array_append(variant_ids_out, current_variant_id) INTO variant_ids_out);
END LOOP;
RETURN variant_ids_out;
END;
$$ LANGUAGE plpgsql;
-- Everything below is included for completeness, but probably less relevant to my question.
CREATE TYPE variant_type AS (
[lots of info about the variant]
);
CREATE OR REPLACE FUNCTION get_variant_id(
variant_in VARIANT_TYPE
) RETURNS INT AS $$
DECLARE variant_id_out INTEGER;
BEGIN
SELECT variant_id into variant_id_out
FROM public.variant
WHERE
[I want them to]
;
RETURN variant_id_out;
END;
$$ LANGUAGE plpgsql;
You can avoid explicit loop using builtin array functions - in this case, unnest function, and array constructor.
CREATE OR REPLACE FUNCTION get_or_create_variant_ids_v2(
variants_in VARIANT_TYPE []
)
RETURNS integer []
LANGUAGE sql AS $$
SELECT ARRAY(
SELECT get_or_create_variant_id(u.v)
FROM unnest(variants_in) AS u(v)
)
$$ LANGUAGE sql;
My code:
CREATE OR REPLACE FUNCTION sizeOfTableFunction
(
p_tableName varchar(100)
)
RETURNS integer
AS $$
DECLARE
p_tableSize integer;
BEGIN
SELECT count(*) into p_tableSize from p_tableName;
return p_tableSize;
END;
$$ LANGUAGE plpgsql STRICT;
Function has been created properly:
CREATE FUNCTION
Execute:
SELECT * FROM sizeOfTableFunction('Run');
Output - problem with executing the function?:
mydb=> SELECT * FROM sizeOfTableFunction('Run');
ERROR: relation "p_tablename" does not exist
LINE 1: SELECT count(*) from p_tableName
^
QUERY: SELECT count(*) from p_tableName
CONTEXT: PL/pgSQL function "sizeoftablefunction" line 5 at SQL statement
You need dynamic SQL for that:
CREATE OR REPLACE FUNCTION sizeOfTableFunction
(
p_tableName varchar(100)
)
RETURNS integer
AS $$
DECLARE
p_tableSize integer;
BEGIN
execute 'SELECT count(*) from '||p_tableName into p_tablesize; -- this is the difference
return p_tableSize;
END;
$$ LANGUAGE plpgsql STRICT;
To be safe, it's better to use the quote_ident function, just in case your tablename contains special characters. It also gives you some protection from SQL injection.
execute 'SELECT count(*) from '||quote_ident(p_tableName) into p_tablesize;
I am trying to create a function that returns a SELECTed resultset.
When I call my postgres function like this select * from tst_dates_func() I get an error as shown below:
ERROR: query has no destination for result data
HINT: If you want to discard the results of a SELECT, use PERFORM instead.
CONTEXT: PL/pgSQL function "tst_dates_func" line 3 at SQL statement
********** Error **********
ERROR: query has no destination for result data
SQL state: 42601
Hint: If you want to discard the results of a SELECT, use PERFORM instead.
Context: PL/pgSQL function "tst_dates_func" line 3 at SQL statement
Here is the function I created:
CREATE OR REPLACE FUNCTION tst_dates_func()
RETURNS TABLE( date_value date, date_id int, date_desc varchar) as
$BODY$
BEGIN
select a.date_value, a.date_id, a.date_desc from dates_tbl a;
END;
$BODY$
LANGUAGE plpgsql;
I am not sure why I am getting the above error. I would like to run select * from tst_dates_func();
and get data back. Or further join the result set if needed. What is the problem here?
Do it as plain SQL
CREATE OR REPLACE FUNCTION tst_dates_func()
RETURNS TABLE( date_value date, date_id int, date_desc varchar) as
$BODY$
select a.date_value, a.date_id, a.date_desc from dates_tbl a;
$BODY$
LANGUAGE sql;
If you really need plpgsql use return query
CREATE OR REPLACE FUNCTION tst_dates_func()
RETURNS TABLE( date_value date, date_id int, date_desc varchar) as
$BODY$
BEGIN
perform SELECT dblink_connect('remote_db');
return query
select a.date_value, a.date_id, a.date_desc from dates_tbl a;
END;
$BODY$
LANGUAGE plpgsql;
In PLPGSQL - use RETURN QUERY
CREATE OR REPLACE FUNCTION tst_dates_func()
RETURNS TABLE( date_value date, date_id int, date_desc varchar) as
$BODY$
BEGIN
RETURN QUERY (select a.date_value, a.date_id, a.date_desc from dates_tbl a);
END;
$BODY$
LANGUAGE plpgsql;
I couldn't do it as plain SQL as I needed to enter some data into a database for further processing and wanted to create a variable. Or at least I did not figure out the correct syntax for that. And the accepted answer had code I did not need, such as connecting to the database, as I ran this from inside pgAdmin with a connection setup already. I also had to drop the function when I made edits to it.
I was using this for inserting a geometry for intersection. A different use case and example could help someone else. This also shows how to then view this data and use it just like a table.
-- Get a geojson shape inside of postgres for further use
DROP FUNCTION fun();
CREATE OR REPLACE FUNCTION fun()
RETURNS TABLE (geometry geometry) AS
$BODY$
DECLARE geojson TEXT;
BEGIN
geojson := '{
"type":"Polygon",
"coordinates":[[[-90.9516399548092,39.8942337977775],[-90.9513913202472,39.8936939306154],[-90.9522805177147,39.8937108246505],[-90.9549542293894,39.8937616571416],[-90.954948768846,39.8945506794343],[-90.9531755591848,39.894492766522],[-90.9531770788457,39.8942868819087],[-90.9516399548092,39.8942337977775]]],
"crs":{"type":"name","properties":{"name":"EPSG:4326"}},
}';
return query (SELECT ST_GeomFromGeoJSON(geojson) AS geometry);
END;
$BODY$
LANGUAGE plpgsql;
-- View test insert
SELECT * FROM fun()
I cannot seem to find a way to pass my query as a parameter to my sql-function. My problem is table 'my_employees1' could be dynamic.
DROP FUNCTION function_test(text);
CREATE OR REPLACE FUNCTION function_test(text) RETURNS bigint AS '
DECLARE ret bigint;
BEGIN
SELECT count(mt.id) INTO ret
FROM mytable as mt
WHERE mt.location_id = 29671
--and mt.employee_id in (SELECT id from my_employees1);
--and mt.employee_id in ($1);
$1;
RETURN ret;
END;
' LANGUAGE plpgsql;
select function_test('and mt.employee_id in (SELECT id from my_employees1)');
select function_test('SELECT id from my_employees1');
It must be dynamically built:
DROP FUNCTION function_test(text);
CREATE OR REPLACE FUNCTION function_test(text) RETURNS bigint AS $$
DECLARE
ret bigint;
BEGIN
execute(format($q$
SELECT count(mt.id) INTO ret
FROM mytable as mt
WHERE mt.location_id = 29671
%s; $q$, $1)
);
RETURN ret;
END;
$$ LANGUAGE plpgsql;
The $$ and $q$ are dollar quotes. They can be nested as long as the inner identifier is different. In addition to the obvious advantages of permitting the use of unquoted quotes and being nestable it also let the syntax highlighting do its work.