splitting characters using function in PostgreSQL - postgresql

Question

I tried to write function like this in PostgreSQL but I'm getting error like
ERROR: syntax error at or near "elems"
LINE 22: RETURN elems;
I want get output like
input: we###ty;rer##2hjjj
output:
we###ty
rer##2hjjj
please help me to solve this error
CREATE OR REPLACE FUNCTION public.fn_split(
inputstr text,
delimeter text)
RETURNS text[]
LANGUAGE 'plpgsql'
COST 100
VOLATILE SECURITY DEFINER PARALLEL UNSAFE
AS $BODY$
DECLARE
delimeter text;
elems text[];
var text;
arr_len int;
BEGIN
SELECT unnest(string_to_array(inputstr,delimeter))
INTO elems
RETURN elems;
END
$BODY$;

Answer 1

CREATE OR REPLACE FUNCTION public.fn_split(
inputstr text,
delimeter text)
RETURNS text[]
LANGUAGE 'plpgsql'
COST 100
VOLATILE SECURITY DEFINER
AS $BODY$
DECLARE
elems text[];
BEGIN
SELECT string_to_array(inputstr,delimeter) INTO elems;
RETURN elems;
END;
$BODY$;
Now call this function like this
SELECT UNNEST(fn_split('1,2,3',',')) as retval
Above is the screenshot which includes function definition and in the first list the command to call this function
Here is the command that you need to execute in order to call this function in the PostgreSQL query window after the creation of the function.

Answer 2

Your function is defined to return an array, however unnest would turn the result of creating the array into rows of strings. There is also no need to duplicate the parameter definition as local variables in a DECLARE block. And as you don't seem to want to manipulate the created array somehow, there is no need to store it in a local variable.
It seems you just want:
CREATE OR REPLACE FUNCTION public.fn_split(
inputstr text,
delimeter text)
RETURNS text[]
LANGUAGE plpgsql
immutable
AS $BODY$
BEGIN
return string_to_array(inputstr,delimeter);
END
$BODY$;
Or simpler as a SQL function:
CREATE OR REPLACE FUNCTION public.fn_split(
inputstr text,
delimeter text)
RETURNS text[]
LANGUAGE sql
immutable
AS
$BODY$
select string_to_array(inputstr,delimeter);
$BODY$;
Note that the language name is an identifier and should not be enclosed in single quotes. This syntax is deprecated and support for it will be removed in a future Postgres version.
Edit:
It seems you don't actually want an array, but one row per element after splitting the input value. In that case the function should be declared as returns table() not returns text[]
CREATE OR REPLACE FUNCTION public.fn_split(
inputstr text,
delimeter text)
RETURNS table(element text)
LANGUAGE sql
immutable
AS
$BODY$
select unnest(string_to_array(inputstr,delimeter));
$BODY$;
Then use it like this:
select *
from fn_split('we###ty;rer##2hjjj', ';');
Since Postgres 14
select unnest(string_to_array(inputstr,delimeter));
can be simplified to
select string_to_table(inputstr,delimeter);