how to set a function parameter like a list - postgresql

I created a function like the following one,
DROP FUNCTION if exists test_list_parameter();
CREATE or REPLACE FUNCTION test_list_parameter(???)
returns setof test
as
$$
select * from test
where test.id in ($1);
$$
language sql
how to set it for querying many ids at the same time?
like the following code,
we need to set the parameter when id more than one, which like (1,2,3,4...) in where clause.
thanks for your help.

Just pass an array of the datatype that of the id. If it's integer, pass a int[] . If it's text, use text[] etc. Also, use ANY instead of IN
CREATE or REPLACE FUNCTION test_list_parameter( idlist int [])
returns setof test
as
$$
select * from test
where test.id = ANY(idlist);
$$
language sql
Call it as
select * from test_list_parameter(ARRAY[1,3]);
DEMO

Related

Call a sequence through a function in PostgreSql

I have a sequence in the database, and I wanted to call the sequence through a function.
I have tried below, need an assistance to create the function in a standard process, as this is not working.
select nextval('code_seq')
CREATE FUNCTION code_sequence(integer) RETURNS integer
LANGUAGE SQL
IMMUTABLE
return select nextval('code_seq');
CREATE FUNCTION local_accounts_sequence(integer) RETURNS integer
LANGUAGE SQL
IMMUTABLE
RETURN (select nextval('code_seq'));
select local_accounts_sequence(1)
check out this solution
I am able to achieve using below statements,
CREATE FUNCTION code_sequence(out seq int)
LANGUAGE plpgsql
as $$
begin
select nextval('code_seq') into seq;
end;$$
try this :
CREATE FUNCTION local_accounts_sequence() RETURNS integer
AS 'SELECT nextval(''code_seq'');'
LANGUAGE SQL;
call it like this :
select local_accounts_sequence();

problem creating PLpgSQL function which accepts ARRAY as INPUT and returns SETOF RECORD from the table

I'm trying to create function which will accept ARRAY as INPUT and then return SETOF RECORD for each of the parameter in ARRAY.
I have table country_regions which consists of 3 Columns: id int, region_name TEXT, country_name TEXT;
My Functions code looks like this:
CREATE OR REPLACE FUNCTION search1(TEXT[])
RETURNS SETOF RECORD AS $$
DECLARE x RECORD;
BEGIN
FOR x IN
SELECT *
FROM company_regions
WHERE country_name = $1::TEXT
LOOP
RETURN NEXT x;
END LOOP;
END; $$
LANGUAGE plpgSQL;
This Function was created successfully, but when I try to call the function like this:
SELECT * FROM search1(ARRAY ['usa', 'canada']) AS search1(id int, region_name TEXT, country_name text)
it returns table with 0 rows in it.
Can someone tell me what am I doing wrong? I'm completely new to SQL, tried to find answer in other post but I still could not figure out the problem.
You try to compare text value versus text[].
CREATE OR REPLACE FUNCTION search1(text[])
RETURNS SETOF company_regions AS $$
BEGIN
RETURN QUERY SELECT * FROM company_regions
WHERE country_name = ANY($1);
END
$$ LANGUAGE plpgsql STABLE
Attention - functions like this are black box for optimizer. Usually is not too good (from performance perspective) using functions like envelops of one SQL statement. In complex query it can block some optimizations (Mainly if you forget to set correct flag of function - in this case STABLE).

What is the datatype required for the IN keyword

I'm trying to create a function in PostgreSQL that uses the keyword IN. For example:
SELECT * FROM test WHERE test.value IN (1,2,23,5,123 ...etc)
I would like to make the part after the IN a function argument. However I don't know what the data type is for this. I've looked at the data type in the docs, but couldn't figure it out.
Complete example:
create function testing(test_value ???) returns SETOF test
stable
language sql
as
$$
SELECT * FROM test WHERE test.value IN test_value
$$;
alter function testing(???) owner to postgres;
You can pass an array and use the ANY operator (the condition IN (...) is being converted to = ANY(array[...])` by the optimizer anyway).
create function testing(test_values int[]) returns SETOF test
stable
language sql
as
$$
SELECT * FROM test WHERE test.value = any(test_values)
$$;
Then use it like this:
select *
from testing(array[1,2,3,4]);

How to return multiple rows from PL/pgSQL function?

I have spent good amount of time trying to figure it out and I haven't been able to resolve it. So, I need your help please.
I am trying to write a PL/pgSQL function that returns multiple rows. The function I wrote is shown below. But it is not working.
CREATE OR REPLACE FUNCTION get_object_fields()
RETURNS SETOF RECORD
AS
$$
DECLARE result_record keyMetrics;
BEGIN
return QUERY SELECT department_id into result_record.visits
from fact_department_daily
where report_date='2013-06-07';
--return result_record;
END
$$ LANGUAGE plpgsql;
SELECT * FROM get_object_fields;
It is returning this error:
ERROR: RETURN cannot have a parameter in function returning set;
use RETURN NEXT at or near "QUERY"
After fixing the bugs #Pavel pointed out, also define your return type properly, or you have to provide a column definition list with every call.
This call:
SELECT * FROM get_object_fields()
... assumes that Postgres knows how to expand *. Since you are returning anonymous records, you get an exception:
ERROR: a column definition list is required for functions returning "record"
One way (of several) to fix this is with RETURNS TABLE (Postgres 8.4+):
CREATE OR REPLACE FUNCTION get_object_fields()
RETURNS TABLE (department_id int) AS
$func$
BEGIN
RETURN QUERY
SELECT department_id
FROM fact_department_daily
WHERE report_date = '2013-06-07';
END
$func$ LANGUAGE plpgsql;
Works for SQL functions just the same.
Related:
PostgreSQL: ERROR: 42601: a column definition list is required for functions returning "record"
I see more bugs:
first, a SET RETURNING FUNCTIONS call has following syntax
SELECT * FROM get_object_fields()
second - RETURN QUERY forwards query result to output directly. You cannot store this result to variable - it is not possible ever in PostgreSQL now.
BEGIN
RETURN QUERY SELECT ....; -- result is forwarded to output directly
RETURN; -- there will not be any next result, finish execution
END;
third - these simple functions is better to implement in SQL languages
CREATE OR REPLACE FUNCTION get_object_fields()
RETURNS SETOF RECORD AS $$
SELECT department_id WHERE ...
$$ LANGUAGE sql STABLE;
Here's one way
drop function if exists get_test_type();
drop type if exists test_comp;
drop type if exists test_type;
drop type if exists test_person;
create type test_type as (
foo int,
bar int
);
create type test_person as (
first_name text,
last_name text
);
create type test_comp as
(
prop_a test_type[],
prop_b test_person[]
);
create or replace function get_test_type()
returns test_comp
as $$
declare
a test_type[];
b test_person[];
x test_comp;
begin
a := array(
select row (m.message_id, m.message_id)
from message m
);
-- alternative 'strongly typed'
b := array[
row('Bob', 'Jones')::test_person,
row('Mike', 'Reid')::test_person
]::test_person[];
-- alternative 'loosely typed'
b := array[
row('Bob', 'Jones'),
row('Mike', 'Reid')
];
-- using a select
b := array (
select row ('Jake', 'Scott')
union all
select row ('Suraksha', 'Setty')
);
x := row(a, b);
return x;
end;
$$
language 'plpgsql' stable;
select * from get_test_type();
CREATE OR REPLACE FUNCTION get_object_fields()
RETURNS table (department_id integer)
AS
$$
DECLARE result_record keyMetrics;
BEGIN
return QUERY
SELECT department_id
from fact_department_daily
where report_date='2013-06-07';
--return result_record;
END;
$$ LANGUAGE plpgsql;
SELECT * FROM get_object_fields()

Optional argument in PL/pgSQL function

I am trying to write a PL/pgSQL function with optional arguments. It performs a query based on a filtered set of records (if specified), otherwise performs a query on the entire data set in a table.
For example (PSEUDO CODE):
CREATE OR REPLACE FUNCTION foofunc(param1 integer, param2 date, param2 date, optional_list_of_ids=[]) RETURNS SETOF RECORD AS $$
IF len(optional_list_of_ids) > 0 THEN
RETURN QUERY (SELECT * from foobar where f1=param1 AND f2=param2 AND id in optional_list_of_ids);
ELSE
RETURN QUERY (SELECT * from foobar where f1=param1 AND f2=param2);
ENDIF
$$ LANGUAGE SQL;
What would be the correct way to implement this function?
As an aside, I would like to know how I could call such a function in another outer function. This is how I would do it - is it correct, or is there a better way?
CREATE FUNCTION foofuncwrapper(param1 integer, param2 date, param2 date) RETURNS SETOF RECORD AS $$
BEGIN
CREATE TABLE ids AS SELECT id from foobar where id < 100;
RETURN QUERY (SELECT * FROM foofunc(param1, param2, ids));
END
$$ LANGUAGE SQL
Since PostgreSQL 8.4 (which you seem to be running), there are default values for function parameters. If you put your parameter last and provide a default, you can simply omit it from the call:
CREATE OR REPLACE FUNCTION foofunc(_param1 integer
, _param2 date
, _ids int[] DEFAULT '{}')
RETURNS SETOF foobar -- declare return type!
LANGUAGE plpgsql AS
$func$
BEGIN -- required for plpgsql
IF _ids <> '{}'::int[] THEN -- exclude empty array and NULL
RETURN QUERY
SELECT *
FROM foobar
WHERE f1 = _param1
AND f2 = _param2
AND id = ANY(_ids); -- "IN" is not proper syntax for arrays
ELSE
RETURN QUERY
SELECT *
FROM foobar
WHERE f1 = _param1
AND f2 = _param2;
END IF;
END -- required for plpgsql
$func$;
Major points:
The keyword DEFAULT is used to declare parameter defaults. Short alternative: =.
I removed the redundant param1 from the messy example.
Since you return SELECT * FROM foobar, declare the return type as RETURNS SETOF foobar instead of RETURNS SETOF record. The latter form with anonymous records is very unwieldy, you'd have to provide a column definition list with every call.
I use an array of integer (int[]) as function parameter. Adapted the IF expression and the WHERE clause accordingly.
IF statements are not available in plain SQL. Has to be LANGUAGE plpgsql for that.
Call with or without _ids:
SELECT * FROM foofunc(1, '2012-1-1'::date);
Effectively the same:
SELECT * FROM foofunc(1, '2012-1-1'::date, '{}'::int[]);
You have to make sure the call is unambiguous. If you have another function of the same name and two parameters, Postgres might not know which to pick. Explicit casting (like I demonstrate) narrows it down. Else, untyped string literals work, too, but being explicit never hurts.
Call from within another function:
CREATE FUNCTION foofuncwrapper(_param1 integer, _param2 date)
RETURNS SETOF foobar
LANGUAGE plgpsql AS
$func$
DECLARE
_ids int[] := '{1,2,3}';
BEGIN
-- whatever
RETURN QUERY
SELECT * FROM foofunc(_param1, _param2, _ids);
END
$func$;
Elaborating on Frank's answer on this thread:
The VARIADIC agument doesn't have to be the only argument, only the last one.
You can use VARIADIC for functions that may take zero variadic arguments, it's just a little fiddlier in that it requires a different calling style for zero args. You can provide a wrapper function to hide the ugliness. Given an initial varardic function definition like:
CREATE OR REPLACE FUNCTION foofunc(param1 integer, param2 date, param2 date, optional_list_of_ids VARIADIC integer[]) RETURNS SETOF RECORD AS $$
....
$$ language sql;
For zero args use a wrapper like:
CREATE OR REPLACE FUNCTION foofunc(integer, date, date) RETURNS SETOF RECORD AS $body$
SELECT foofunc($1,$2,$3,VARIADIC ARRAY[]::integer[]);
$body$ LANGUAGE 'sql';
or just call the main func with an empty array like VARIADIC '{}'::integer[] directly. The wrapper is ugly, but it's contained ugliness, so I'd recommend using a wrapper.
Direct calls can be made in variadic form:
SELECT foofunc(1,'2011-01-01','2011-01-01', 1, 2, 3, 4);
... or array call form with array ctor:
SELECT foofunc(1,'2011-01-01','2011-01-01', VARIADIC ARRAY[1,2,3,4]);
... or array text literal form:
SELECT foofunc(1,'2011-01-01','2011-01-01', VARIADIC '{1,2,3,4}'::int[]);
The latter two forms work with empty arrays.
You mean SQL Functions with Variable Numbers of Arguments? If so, use VARIADIC.