Stored procedure syntax with IN condition - arrays

Question

(1)
=>CREATE TABLE T1(id BIGSERIAL PRIMARY KEY, name TEXT);
CREATE TABLE
(2)
=>INSERT INTO T1
(name) VALUES
('Robert'),
('Simone');
INSERT 0 2
(3)
SELECT * FROM T1;
id | name
----+--------
1 | Robert
2 | Simone
(2 rows)
(4)
CREATE OR REPLACE FUNCTION test_me(id_list BIGINT[])
RETURNS BOOLEAN AS
$$
BEGIN
PERFORM * FROM T1 WHERE id IN ($1);
IF FOUND THEN
RETURN TRUE;
ELSE
RETURN FALSE;
END IF;
END;
$$
LANGUAGE 'plpgsql';
CREATE FUNCTION
My problem is when calling the procedure. I'm not able to find an example on the net showing how to pass a list of values of type BIGINT (or integer, whatsoever).
I tried what follows without success (syntax errors):
First syntax:
eway=> SELECT * FROM test_me('{1,2}'::BIGINT[]);
ERROR: operator does not exist: bigint = bigint[]
LINE 1: SELECT * FROM T1 WHERE id IN ($1)
^
HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
QUERY: SELECT * FROM T1 WHERE id IN ($1)
CONTEXT: PL/pgSQL function test_me(bigint[]) line 3 at PERFORM
Second syntax:
eway=> SELECT * FROM test_me('{1,2}');
ERROR: operator does not exist: bigint = bigint[]
LINE 1: SELECT * FROM T1 WHERE id IN ($1)
^
HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
QUERY: SELECT * FROM T1 WHERE id IN ($1)
CONTEXT: PL/pgSQL function test_me(bigint[]) line 3 at PERFORM
Third syntax:
eway=> SELECT * FROM test_me(ARRAY [1,2]);
ERROR: operator does not exist: bigint = bigint[]
LINE 1: SELECT * FROM T1 WHERE id IN ($1)
^
HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
QUERY: SELECT * FROM T1 WHERE id IN ($1)
CONTEXT: PL/pgSQL function test_me(bigint[]) line 3 at PERFORM
Any clues about a working syntax?
It's like the parser was trying to translate a BIGINT to BIGINT[] in the PEFORM REQUEST but it doesn't make any sense to me...

Answer 1

All your syntax variants to pass an array are correct.
Pass array literal to PostgreSQL function
The problem is with the expression inside the function. You can test with the ANY construct like #Mureinik provided or a number of other syntax variants. In any case run the test with an EXISTS expression:
CREATE OR REPLACE FUNCTION test_me(id_list bigint[])
RETURNS bool AS
$func$
BEGIN
IF EXISTS (SELECT 1 FROM t1 WHERE id = ANY ($1)) THEN
RETURN true;
ELSE
RETURN false;
END IF;
END
$func$ LANGUAGE plpgsql STABLE;
Notes
EXISTS is shortest and most efficient:
PL/pgSQL checking if a row exists - SELECT INTO boolean
The ANY construct applied to arrays is only efficient with small arrays. For longer arrays, other syntax variants are faster. Like:
IF EXISTS (SELECT 1 FROM unnest($1) id JOIN t1 USING (id)) THEN ...
How to do WHERE x IN (val1, val2,…) in plpgsql
Don't quote the language name, it's an identifier, not a string: LANGUAGE plpgsql
Simple variant
While you are returning a boolean value, it can be even simpler. It's probably just for the demo, but as a proof of concept:
CREATE OR REPLACE FUNCTION test_me(id_list bigint[])
RETURNS bool AS
$func$
SELECT EXISTS (SELECT 1 FROM t1 WHERE id = ANY ($1))
$func$ LANGUAGE sql STABLE;
Same result.

Answer 2

The easiest way to check if an item is in an array is with = ANY:
CREATE OR REPLACE FUNCTION test_me(id_list BIGINT[])
RETURNS BOOLEAN AS
$$
BEGIN
PERFORM * FROM T1 WHERE id = ANY ($1);
IF FOUND THEN
RETURN TRUE;
ELSE
RETURN FALSE;
END IF;
END;
$$
LANGUAGE 'plpgsql';