query has no destination for result data [duplicate] - postgresql

Question

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Error: query has no destination for result data while using a cursor
(2 answers)
Function with SQL query has no destination for result data
(3 answers)
Closed 8 years ago.
i have table like below with name student
S.No Name
1. Ramesh
2. Raju
3. SOmu
-------------
------------- etc
My requirement is when i am passing the S.no i will get the Name by using function
My function like below:
CREATE OR REPLACE FUNCTION fn_name(v_sno bigint)
RETURNS TEXT
AS
$BODY$
DECLARE RESULT VARCHAR(5000);
BEGIN
SELECT RESULT "Name" FROM "Student" WHERE "s.no" = v_sno;
RETURN RESULT;
END;
$BODY$
LANGUAGE plpgsql
COST 100;
ALTER FUNCTION fn_name(bigint)
OWNER TO postgresql
but i am getting the following 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 fn_name(bigint) line 6 at SQL statement
please help me how to resolve the above issue.

Answer 1

The immediate question is easily answered by the manual (see SELECT INTO).
However, all that is a rather overcomplicated way to do what you want. Things notably wrong:
varchar(5000) is weird and unnecessary. Use text or unqualified varchar.
SELECT RESULT "Name" doesn't do what you probably think it does. That's trying to SELECT a column named result and alias it as Name. I think you were looking for SELECT INTO.
"s.no" means the column named s.no. Is that what you meant? Because that's a horrid name for a column; without the quotes it'd be interpreted as the column no from the table s. Don't use periods in column names or table names.
All you really need is:
CREATE OR REPLACE FUNCTION fn_name(bigint)
RETURNS TEXT AS
$BODY$
SELECT "Name" FROM "Student" WHERE "s.no" = $1;
$BODY$
LANGUAGE sql;
(assuming "s.no" really is your column name, not a mangled attempt at an alias).
If you had to use PL/PgSQL for this simple job for some reason (maybe you intend to make it more complex later), you'd write:
CREATE OR REPLACE FUNCTION fn_name(v_sno bigint)
RETURNS TEXT AS
$BODY$
DECLARE
result text;
BEGIN
SELECT INTO result "Name" FROM "Student" WHERE "s.no" = $1;
RETURN result;
END;
$BODY$
LANGUAGE plpgsql;