I'm trying to use a plgSQL witch return me a record type :
CREATE FUNCTION actu(id INTEGER) RETURNS RECORD AS $$
DECLARE
ret RECORD;
BEGIN
SELECT id_photo, id_user, lien, titre
FROM photo
WHERE id_user IN (
SELECT id_userabo
FROM abo
WHERE id_user = id )
ORDER BY date_publi DESC LIMIT 10;
RETURN ret;
END;$$
LANGUAGE plpgsql;
When I'm trying to use it with :
SELECT * FROM actu(4)
AS (id_photo Integer, id_photo Integer, lien Varchar, titre Varchar);
pgAdmin4 send me error :
ERROR: ERROR: the request has no destination for the resulting data
HINT: If you want to cancel the results of a SELECT, use PERFORM instead.
CONTEXT: PL/pgsql function fil_actu(integer), line 5 with SQL statement
The immediate error is, that the result of a select statement needs to be stored somewhere (that's what the error says). You would need to use select .. into ret from ... to store the result, but that wouldn't work as a variable of type record can only store one row from a result.
You apparently want to return more than just one row, so you need to define the function as returns table() and then use return query in PL/pgSQL to return the result of a query. But for a simple function encapsulating a SELECT query, a language sql function is more efficient.
CREATE FUNCTION actu(id INTEGER)
-- adjust the data types for the returned columns!
RETURNS table (id_photo int, id_user int, lien text, titre text)
AS $$
SELECT id_photo, id_user, lien, titre
FROM photo
WHERE id_user IN (SELECT id_userabo
FROM abo
WHERE id_user = id )
ORDER BY date_publi DESC
LIMIT 10;
$$
LANGUAGE sql;
You can use that function like this:
select *
from actu(42);
You may define those types inside the function, but with different names for the types. The return type can be a TABLE type and use RETURN QUERY to return the results.
CREATE FUNCTION actu(id INTEGER) RETURNS TABLE
(typ_id_photo Integer, typ_id_user Integer, typ_lien Varchar, typ_titre Varchar)
AS $$
BEGIN
RETURN QUERY
SELECT id_photo, id_user, lien, titre
FROM photo p
WHERE id_user IN (SELECT id_userabo
FROM abo
WHERE id_user = id )
ORDER BY date_publi DESC
LIMIT 10;
END;$$
LANGUAGE plpgsql;
Related
I am trying to fetch data from remote db by using dblink through function but getting an error "query has no destination for result data". I am using plpgsql language to do the same.
Function:
CREATE OR REPLACE FUNCTION fun()
RETURNS text AS
$$
begin
select dblink_connect(
'port=5432 dbname=test user=postgres password=****');
WITH a AS (
SELECT *
FROM dblink(
'SELECT slno,fname,mname,lname
FROM remote_tbl'
) AS t (slno int, fname text, mname text, lname text)
)
, b AS (
INSERT INTO temptab1
SELECT slno, name
FROM a
)
, c AS (
INSERT INTO temptab2
SELECT slno, name
FROM a
)
INSERT INTO temptab3
SELECT slno, name
FROM a;
select dblink_disconnect();
end;
$$
LANGUAGE plpgsql;
Calling Function:
select fun();
Error: query has no destination for result data
The stored procedure won't just return the result of the last SELECT. You need to actually return the value:
CREATE OR REPLACE FUNCTION fun() RETURNS text AS $$
BEGIN
--- ....
RETURN(SELECT dblink_disconnect());
END
$$ LANGUAGE plpgsql;
You're getting the error because Postgres expects the function to return something of type text, but your function doesn't return anything.
Use a plain SQL function instead of PL/PgSQL, or use SELECT INTO and ordinary RETURN.
Reason for the error you're getting is because there is no return in between your BEGIN and END for example:
BEGIN
update mytable set lastcodeused = to_char(cast(lastcodeused as INTEGER)+1, 'FM999999999999999999') where
classid = classIdVar and appid= appIdInt
RETURNING concat(pageUniqueCode,lastcodeused) as pageUniqueCode
into taskcode;
return taskcode;
END;
If you have this error using a pgplsql procedure or function, and you are sure that the return is defined correctly, there exists a different non-intuitive cause. I needed some time to realize this so I think it is worth sharing. I had a function like this:
CREATE OR REPLACE FUNCTION "db".fn_x(
id integer)
RETURNS TABLE(b_val varchar(100), c_val varchar(100))
LANGUAGE 'plpgsql'
AS $BODY$
DECLARE
var_b_val varchar(100);
var_c_val varchar(100);
BEGIN
select var_b, var_c
-- Missing INTO clause was the cause of the error.
var_b_val, var_c_val
from "db".table_y where y_id = id;
return query(select var_b_val, var_c_val);
END;
$BODY$;
Just adding that missing INTO clause made the function work correctly.
In conclusion, this error can also trigger on silent syntax errors.
New to Stored Procedures , have a requirement where I need to execute multiple queries inside stored procedure and return results. I would like to know whether this is possible or not ..
Ex :
Query 1 returns a list of userid ..
Select userid from user where username = ?
For each userid from the above query , I need to execute three different queries like
Query 2 select session_details from session where userid = ?
Query 3 select location from location where userid = ?
The return value should be a collection of , session_details and location.
Is this possible,can you provide some hints?
You can loop through query results like so:
FOR id IN Select userid from user where username = ?
LOOP
...
END LOOP;
As #Fahad Anjum says in his comment, its better if you can do it in a query. But if that's not posible, you have tree posibilities to achive what you want.
SETOF
TABLE
refcursor
1. SETOF
You can return a set of values. The set can be an existing table, a temporal table, or a TYPE you define.
TYPE example:
-- In your case the type could be (userid integer, session integer, location text)
CREATE TYPE tester AS (id integer);
-- The pl returns a SETOF the created type.
CREATE OR REPLACE FUNCTION test() RETURNS SETOF tester
AS $$
BEGIN
RETURN QUERY SELECT generate_series(1, 3) as id;
END;
$$ LANGUAGE plpgsql
-- Then, you get the set by selecting the PL as if it were a table.
SELECT * FROM test();
Table and Temp Table examples:
-- Create a temporal table o a regular table:
CREATE TEMP TABLE test_table(id integer);
-- or CREATE TABLE test_table(id integer);
-- or use an existing table in your schema(s);
-- The pl returns a SETOF the table you need
CREATE OR REPLACE FUNCTION test() RETURNS SETOF test_table
AS $$
BEGIN
RETURN QUERY SELECT generate_series(1, 3) as id;
END;
$$ LANGUAGE plpgsql
-- Then, you get the set by selecting the PL as if it were a table.
SELECT * FROM test();
-- NOTE: Since you are only returning a SETOF the table,
-- you don't insert any data into the table.
-- So, if you select the 'temp' table you won't see any changes.
SELECT * FROM test_table
2. TABLE
A PL can return a table, it would be similar to create a temporal table and then return a SETOF, but, in this case you declare de 'temp' table on the 'returns' sentence of the PL.
-- Next to TABLE you define the columns of the table the PL will return
CREATE OR REPLACE FUNCTION test() RETURNS TABLE (id integer)
AS $$
BEGIN
RETURN QUERY SELECT generate_series(1, 3) as id;
END;
$$ LANGUAGE plpgsql
-- As the other examples, you select the PL to get the data.
SELECT * FROM test();
3. refcursor
This one is the more complex solution. You return a cursor, not the actual data. If you need 'dynamic' values for your returning set, this is the solution.
But since you need static data, you won't need this option.
The use of any of these ways depends on any specific case, if you use regularly the userid,session,location in different ways and PLs, it would be better to Use the SETOF with a type.
If you have a table that has the userid,session,location columns, it's better to return a SETOF table.
If you just use the userid,session,location for one case, then it would be better to use a 'RETURNS TABLE' approach.
If you need to return a dynamic set you would have to use cursors... but that solution is really more advanced.
Based solely on your example, here's probably the easiest way to do it:
CREATE FUNCTION my_func(user_id INTEGER)
RETURNS TABLE (userid INTEGER, session INTEGER, location TEXT) AS
$$
SELECT u.userid, s.session, l.location
FROM -- etc... your query here
$$
LANGUAGE SQL STABLE;
Addressing comment:
That's a bit of a different question. One question is how to return multiple records containing multiple fields in a stored procedure. One way is as above.
The other question is how to write a query that gets data from multiple tables. Again, there are many ways to do it. One way is (again, based on my interpretation of your requirements in the examples):
SELECT userid
, ARRAY_AGG(SELECT session_details FROM session s WHERE s.userid = u.userid)
, ARRAY_AGG(SELECT l.location FROM location l WHERE l.userid = u.userid)
FROM user u
WHERE username = user_name
This will return one record containing the user_id, an array of session_details for that user, and an array of locations for that user.
Then the function can be changed to:
CREATE FUNCTION my_func(user_name TEXT, OUT userid INTEGER, OUT session_details TEXT[], OUT locations TEXT[])
AS $$
SELECT userid
, ARRAY(SELECT session_details FROM session s WHERE s.userid = u.userid)
, ARRAY(SELECT l.location FROM location l WHERE l.userid = u.userid)
FROM user u
WHERE username = user_name;
$$ LANGUAGE SQL STABLE;
I am trying to fetch data from remote db by using dblink through function but getting an error "query has no destination for result data". I am using plpgsql language to do the same.
Function:
CREATE OR REPLACE FUNCTION fun()
RETURNS text AS
$$
begin
select dblink_connect(
'port=5432 dbname=test user=postgres password=****');
WITH a AS (
SELECT *
FROM dblink(
'SELECT slno,fname,mname,lname
FROM remote_tbl'
) AS t (slno int, fname text, mname text, lname text)
)
, b AS (
INSERT INTO temptab1
SELECT slno, name
FROM a
)
, c AS (
INSERT INTO temptab2
SELECT slno, name
FROM a
)
INSERT INTO temptab3
SELECT slno, name
FROM a;
select dblink_disconnect();
end;
$$
LANGUAGE plpgsql;
Calling Function:
select fun();
Error: query has no destination for result data
The stored procedure won't just return the result of the last SELECT. You need to actually return the value:
CREATE OR REPLACE FUNCTION fun() RETURNS text AS $$
BEGIN
--- ....
RETURN(SELECT dblink_disconnect());
END
$$ LANGUAGE plpgsql;
You're getting the error because Postgres expects the function to return something of type text, but your function doesn't return anything.
Use a plain SQL function instead of PL/PgSQL, or use SELECT INTO and ordinary RETURN.
Reason for the error you're getting is because there is no return in between your BEGIN and END for example:
BEGIN
update mytable set lastcodeused = to_char(cast(lastcodeused as INTEGER)+1, 'FM999999999999999999') where
classid = classIdVar and appid= appIdInt
RETURNING concat(pageUniqueCode,lastcodeused) as pageUniqueCode
into taskcode;
return taskcode;
END;
If you have this error using a pgplsql procedure or function, and you are sure that the return is defined correctly, there exists a different non-intuitive cause. I needed some time to realize this so I think it is worth sharing. I had a function like this:
CREATE OR REPLACE FUNCTION "db".fn_x(
id integer)
RETURNS TABLE(b_val varchar(100), c_val varchar(100))
LANGUAGE 'plpgsql'
AS $BODY$
DECLARE
var_b_val varchar(100);
var_c_val varchar(100);
BEGIN
select var_b, var_c
-- Missing INTO clause was the cause of the error.
var_b_val, var_c_val
from "db".table_y where y_id = id;
return query(select var_b_val, var_c_val);
END;
$BODY$;
Just adding that missing INTO clause made the function work correctly.
In conclusion, this error can also trigger on silent syntax errors.
Example: I am passing two parameters to function namely n(case number) and tname(table name), and want to display rows accordingly.
--Table "testing"
create table testing
(
rollno integer,
fname text,
lname text,
age integer,
branch text,
phno integer,
email text,
address text,
city text,
state text,
country text
)
--Rows insertion
insert into testing values(1,'aaa','bbb',25,'CS',1234567890,'abc#gmail.com','sector1','xyz','zyx','yxz');
insert into testing values(2,'zzz','xxx',25,'EE',987654321,'zzz#gmail.com','sector2','uvw','wvu','vuw');
--Function "f1()"
create or replace function f1(n integer,tname varchar)/*n for case number and tname for table name */
returns setof tname as
$body$
begin
case n
when 1 then
return query execute format ($$ select rollno,fname from %I $$,tname);
when 2 then
return query execute format ($$ select lname,age,branch from %I $$,tname);
when 3 then
return query execute format ($$ select phno,email,address,city,country from %I $$,tname);
end case;
end
$body$
language plpgsql;
--Function calling
select * from f1(1,'testing');
/*Show only case "1" select query result*/
select * from f1(2,'testing');
/*Show only case "2" select query result*/
select * from f1(3,'testing');
/*Show only case "3" select query result*/
While Craig is correct that return types cannot be dynamic in function declarations, there is a way around this with polymorphic types. This is surprisingly simple and would actually work flawlessly:
CREATE OR REPLACE FUNCTION data_of(_tbl_type anyelement)
RETURNS SETOF anyelement AS
$func$
BEGIN
RETURN QUERY EXECUTE 'SELECT * FROM '|| pg_typeof(_tbl_type);
END
$func$ LANGUAGE plpgsql;
Call (important!):
SELECT rollno,fname FROM data_of(NULL::testing);
SELECT * FROM data_of(NULL::my_schema.my_table);
SELECT * FROM data_of(NULL::my_custom_type);
What you need is a well-known type. For every table there is a well-known type automatically. But you can create any type, cast NULL to it and pass it to the function. This way you can build exactly what you have in your question ...
Related answer with a lot more details:
Refactor a PL/pgSQL function to return the output of various SELECT queries
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()