For the first time I'm trying to create function in PostgreSQL:
This function must accept parameter with array type. Array contains sequence of biginteger values. Size of array not arbitrary, but known in advance.
create function get_total (cols ARRAY) returns biginteger AS
$BODY$
begin
// Some logics
end;
$BODY$
Usage in query
select
stats.value1,
stats.value2,
get_total(array_agg(ARRAY[stats.value2, stats.value1]))
from stats;
It returns error:
type cols[] does not exist
SQL state: 42704
When I run in Select only array_agg(ARRAY[stats.value2, stats.value1]), I see, that array created successfully. So the problem in function parameter.
What am I doing wrong?
You have to declare the parameter as bigint[], which reads an array of type bigint e.g.
CREATE OR REPLACE FUNCTION get_total (bigint[])
RETURNS bigint AS
$$
BEGIN
-- your fancy logic goes here
END;
$$ LANGUAGE plpgsql
Function call:
SELECT get_total(ARRAY[1111111111111,1111111111111]);
An elegant alternative is to declare the parameter as VARIADIC. Doing so you may call your function with multiple parameters,e.g.:
CREATE OR REPLACE FUNCTION get_total (VARIADIC bigint[])
RETURNS bigint AS
$$
BEGIN
-- your fancy logic goes here
END;
$$ LANGUAGE plpgsql;
Function call:
SELECT get_total(1111111111111,1111111111111,1111111111111);
Demo: db<>fiddle
The syntax cols ARRAY is the same as cols[] and means “an array with elements of type cols”. That's why you get that error message for the function definition.
If the element type is bigint, the function should be defined as
CREATE FUNCTION get_total(cols bigint ARRAY) RETURNS bigint
Related
I'm new to Postgres and currently trying to write a function that takes in an integer and then calls another (definitely working) pre-written function with that input. If I call the pre-written function directly, e.g.:
select * from func(3456789);
I get the result I expect, with no errors. However, if I call it inside my function:
create or replace function my_func(_id integer)
returns setof Record
as $$
declare
rec Record;
begin
for rec in
select * from func(_id)
loop
return next rec;
end loop;
end;
$$ language plpgsql
;
where I call it with exactly the same parameter:
select * from my_func(3456789);
I get the following error:
ERROR: value too long for type character(4)
CONTEXT: PL/pgSQL function my_func(integer) line 5 at FOR over SELECT rows
Why are these two cases different, and how can I fix it?
EDIT:
func(_sid) returns this:
CREATE FUNCTION func(_sid integer) RETURNS SETOF Record
LANGUAGE plpgsql
AS $$ ...
and Record is defines like this:
create type Record as (code char(8), name char(4), num integer, work char(4));
Every line that is returned by your function func is mapped to a Record.
So the error you are getting says that one of the lines in the function result contains at column positions of name and/or work a value bigger than the one required by the columns (wich is 4).
I've got a postgresql stored procedure, which is returning an integer.
When I call that function, the result is returned with the function name as column name.
For example the name of the function is: "add-person". The column name, when invoking the function, is "add-person".
Is there a way to make the database return the integer with a self-choosen column name? For example "id"?
I think it is pretty easy, but I currently miss the forests for the trees..
Edit:
What i'd missed to tell, is that the return value is a variable, like so:
CREATE OR REPLACE FUNCTION "scheme"."add-person"(arggivenname character varying, argfamilyname character varying) RETURNS integer AS
$BODY$
DECLARE
varResponse integer;
BEGIN
-- Operations before
INSERT INTO "scheme"."table"
(
given_name,
family_name
)
VALUES
(
arggivenname,
argfamilyname
)
RETURNING
"id"
INTO
varResponse;
-- Operations after
RETURN varResponse;
END;
$BODY$
LANGUAGE plpgsql VOLATILE COST 100;
You can us the AS statement for that. That means:
Select add-person() AS yourcolumnname
To have a named column from a function it is necessary to create a type and return that type from the function
create type mytype as (mycolumn integer);
create or replace function ri()
returns mytype as $$
select 1;
$$ language sql;
select * from ri();
mycolumn
----------
1
Edit
Or much simpler without the type creation as in #pozs comment:
create or replace function ri(out mycolumn integer)
as $$
select 1;
$$ language sql;
The following code that I use returns an integer 1:
CREATE TYPE my_test AS (
foo Integer
);
CREATE FUNCTION foo_out()
RETURNS SETOF Integer AS
$$
BEGIN
RETURN QUERY
SELECT 1 as foo;
END
$$
LANGUAGE plpgsql;
CREATE FUNCTION foo1()
RETURNS SETOF my_test
AS $$
DECLARE
x my_test;
BEGIN
FOR x IN
SELECT foo_out()
LOOP
RETURN NEXT x;
END LOOP;
END;
$$
LANGUAGE 'plpgsql';
select * from foo1();
But why does the same code return:
ERROR: invalid input syntax for integer: (1)
if I change the return type to:
CREATE FUNCTION foo_out()
RETURNS SETOF my_test
Which also should be an integer!? It could be the case that the system differs between the type integer and a custom type that includes an integer. What should be changed that the use of custom types is possible here?
my_test is a composite type, a row type, that contains a single integer field. It's not an integer.
When assigning to a record or row type in a FOR loop all output columns from the query form the row. Your SELECT needs to return a single, unnested integer column, which is then nested into a row type matching your custom type my_test.
You can also assign to a list of scalar variables in a FOR loop, in which case columns from the query are assigned left to right to variables as is - not forming a row.
If the column itself is a row type, you have one level of nesting to many. The text representation of a row containing an integer field is '(1)' (with parentheses!), and that's what you see in the error message.
You can fix that by extracting the integer field from the row with attribute notation:
SELECT (foo_out()).*
Or (more efficiently for multiple columns) by decomposing with:
SELECT * FROM foo_out()
Example Code
CREATE FUNCTION foo_out()
RETURNS SETOF my_test
LANGUAGE sql AS
'SELECT ''(1)''::my_test';
CREATE FUNCTION foo1()
RETURNS SETOF my_test
LANGUAGE plpgsql AS
$func$
DECLARE
x my_test;
BEGIN
FOR x IN
SELECT * FROM foo_out()
LOOP
RETURN NEXT x;
END LOOP;
END
$func$;
db<>fiddle here
Old sqlfiddle
Don't quote the language name plpgsql. It's an identifier.
Remember that looping is rarely needed, since most problems are more efficiently solved with a set-based approach (SQL only).
Related answers by Craig and Pavel:
Passing array of a composite type to stored procedure
I have an error, but I don't know what the problem is.
I want execute a function and return a value from a column filled in by the column default, a sequence - the equivalent of currval(sequence).
I use:
PostgreSQL 9.0
pgAdmin III
CREATE OR REPLACE FUNCTION name_function(in param_1 character varying
, out param_2 bigint)
AS
$$
BEGIN
INSERT INTO table (collumn_seq,param_1) VALUES (DEFAULT,param_1)
returning collumn_seq;
--where:collumn_seq reference a collumn serial..
END;
$$
LANGUAGE plpgsql VOLATILE;
I can create the function without error but when trying to execute, the following error is returned:
SELECT name_function('GHGHGH');
ERROR: The query has no destination for result data
It would work like this:
CREATE OR REPLACE FUNCTION name_function(param_1 varchar
, OUT param_2 bigint)
LANGUAGE plpgsql AS
$func$
BEGIN
INSERT INTO table (collumn_seq, param_1) -- "param_1" also the column name?
VALUES (DEFAULT, param_1)
RETURNING collumn_seq
INTO param2;
END
$func$;
Normally, you would add a RETURN statement, but with OUT parameters, this is optional.
Refer to the manual for more details:
Returning from a function
Executing a Query with a Single-row Result
The simple case can be covered with a plain SQL function.
And you can omit the target column that shall get its DEFAULT value.
And you can just as well use a RETURNS clause in this case:
CREATE OR REPLACE FUNCTION name_function(param_1 varchar)
RETURNS bigint
LANGUAGE sql AS
$func$
INSERT INTO table (param_1) -- "param_1" also the column name?
VALUES (param_1)
RETURNING collumn_seq;
$func$;
I have a function defined as follows:
CREATE OR REPLACE FUNCTION public.somefcn(
_somevar enum_my_type
)
RETURNS integer AS
$body$
DECLARE
ret_id INTEGER
BEGIN
INSERT INTO mytable(somevar) VALUES (_somevar) RETURNING id INTO ret_id;
RETURN ret_id;
END;
$body$
LANGUAGE 'plpgsql'
When I call this like this
SELECT somefcn('validenumitem');
I get this error:
ERROR: column "somevar" is of type enum_my_type but expression is of type text
How should I update my function or call to make it work?
Found it. I had another, incorrect function as
CREATE OR REPLACE FUNCTION public.somefcn(
_somevar text
)
...
Apparently, PostgreSQL took that one, because it fits better.