I am new to SQL, so please try not to be overly critical about my question, I need to create a function which would return me a table (say for example "machine") , which would have a column called "aggtablename" and the rows would be filled with values derived from a database. Here is what i tried and the following error came....so please help me in making my syntax correct, THANKS..
CREATE FUNCTION aggtable() RETURNS TABLE (machineid, serveraggtablename)
AS $table$
BEGIN
RETURN QUERY
SELECT m.machineid, m.serveraggtablename
FROM machine m
END;
$table$
LANGUAGE plpgsql;
select aggtable();
ERROR: function aggtable() does not exist LINE 1: select aggtable();
^ HINT: No function matches the given name and argument types. You might need to add explicit type casts.
The arguments of the table you're returning do not have any type.
try adding a type such as machineid int.
check this post
How can a Postgres Stored Function return a table
Try this
CREATE TYPE machineType as (machineid int, serveraggtable character varying);
CREATE FUNCTION aggtable() RETURNS SETOF machineType AS
'SELECT m.machineid, m.serveraggtablename FROM machine m;'
LANGUAGE 'sql';
SELECT * FROM aggtable();
https://wiki.postgresql.org/wiki/Return_more_than_one_row_of_data_from_PL/pgSQL_functions
Related
I have problem with return table using SQL Procedure.
My code:
CREATE PROCEDURE return_data(surname character varying)
LANGUAGE SQL
AS $$
SELECT * FROM peopple WHERE surname=surname
$$;
CALL return_data('Jobs');
Currently the procedure executes without error but it doesn't return a table.
Procedures aren't meant to return anything. Use a set returning function
create function return_data(p_surname varchar)
returns setof people
as
$$
select *
from people
where surname = p_surname;
$$
language sql;
You should also avoid parameter or variable names that have the same name as a column.
Then use it like this:
select *
from return_data('Jobs');
You can append one or more rows to the result set:
CREATE OR REPLACE FUNCTION return_data(surname character varying)
RETURNS TABLE(firstname character varying, surname character varying, age integer)
LANGUAGE plpgsql
AS $function$
BEGIN
RETURN QUERY
SELECT firstname, surname, age
FROM users;
END;
$function$
;
Invoke the function:
SELECT * FROM return_data("a surname");
A function can return but a procedure cannot. Thats true, I wanna add to that we generally use function to return values of one type (in general one value)
While,
Procedure never returns but can behave like a function without a return statement using OUT parameters. To add to this we use procedure when we dont wanna return in actual but executing sql statements but in case if we require a procedure to give multiple values we can make procedure behave like a function for multole values output vja OUT.
As a table can be accessed by record or array type depending upon homogenity. Therefore, use function with return type as record/array.
Hence, as function is solely used to return single output we have to specify via return.
A novice when it comes to stored procedures/functions. I have searched Google, Stackoverflow, and Youtube and are finding all sorts of examples that are convoluted, some not in English.
I'm trying to understand the basic syntax for a stored function to return a table in Postgresql. In MySql this is elementary but I can't seem to wrap my head around the syntax for Postgresql I have the SQL statement I need to return the rows I want (table), as seen below. I have tried the following code but it doesn't work. Help is much appreciated, thanks in advance.
CREATE OR REPLACE FUNCTION Getcurrent()
RETURNS table AS $schedule$
$BODY$ BEGIN
SELECT *
FROM archived_table
WHERE table_id>=ALL(SELECT table_id FROM archived_table);
RETURN schedule;
END;$BODY$
LANGUAGE plpgsql;
********** Error **********
ERROR: syntax error at or near "AS"
LINE 2: RETURNS table AS $schedule$
^
This is the error message.
I have referenced the following link and have had no luck with this.https://www.postgresql.org/docs/9.1/static/sql-createfunction.html
Im using pgAdminIII, in the public schema, on my company's server.
The desired results is to have the table returned once the function is called.
RETURNS TABLE is not complete, hence the error message.
You can use the RETURNS SETOF <table_name> form, if you intend to return all columns of a table.
Otherwise, you'll need to mention every output column by name and type, with either RETURNS TABLE:
RETURNS TABLE (
col_alias_1 INT,
col_alias_2 TEXT,
col_alias_3 <some_other_type>,
...
)
Or with OUT parameters + RETURNS SETOF RECORD to indicate that you'll (possibly) return multiple rows at once.
Also, if your operation is as simple as a few SQL statements, use LANGUAGE SQL instead:
CREATE OR REPLACE FUNCTION Getcurrent()
RETURNS SETOF archived_table
LANGUAGE SQL
AS $BODY$
SELECT *
FROM archived_table
WHERE table_id>=ALL(SELECT table_id FROM archived_table);
$BODY$;
I would like to use a plpgsql function with a table and several columns as input parameter. The idea is to split the table in chunks and do something with each part.
I tried the following function:
CREATE OR REPLACE FUNCTION my_func(Integer)
RETURNS SETOF my_part
AS $$
DECLARE
out my_part;
BEGIN
FOR i IN 0..$1 LOOP
FOR out IN
SELECT * FROM my_func2(SELECT * FROM table1 WHERE id = i)
LOOP
RETURN NEXT out;
END LOOP;
END LOOP;
RETURN;
END;
$$
LANGUAGE plpgsql;
my_func2() is the function that does some work on each smaller part.
CREATE or REPLACE FUNCTION my_func2(table1)
RETURNS SETOF my_part2 AS
$$
BEGIN
RETURN QUERY
SELECT * FROM table1;
END
$$
LANGUAGE plpgsql;
If I run:
SELECT * FROM my_func(99);
I guess I should receive the first 99 IDs processed for each id.
But it says there is an error for the following line:
SELECT * FROM my_func2(select * from table1 where id = i)
The error is:
The subquery is only allowed to return one column
Why does this happen? Is there an easy way to fix this?
There are multiple misconceptions here. Study the basics before you try advanced magic.
Postgres does not have "table variables". You can only pass 1 column or row at a time to a function. Use a temporary table or a refcursor (like commented by #Daniel) to pass a whole table. The syntax is invalid in multiple places, so it's unclear whether that's what you are actually trying.
Even if it is: it would probably be better to process one row at a time or rethink your approach and use a set-based operation (plain SQL) instead of passing cursors.
The data types my_part and my_part2 are undefined in your question. May be a shortcoming of the question or a problem in the test case.
You seem to expect that the table name table1 in the function body of my_func2() refers to the function parameter of the same (type!) name, but this is fundamentally wrong in at least two ways:
You can only pass values. A table name is an identifier, not a value. You would need to build a query string dynamically and execute it with EXECUTE in a plpgsql function. Try a search, many related answers her on SO. Then again, that may also not be what you wanted.
table1 in CREATE or REPLACE FUNCTION my_func2(table1) is a type name, not a parameter name. It means your function expects a value of the type table1. Obviously, you have a table of the same name, so it's supposed to be the associated row type.
The RETURN type of my_func2() must match what you actually return. Since you are returning SELECT * FROM table1, make that RETURNS SETOF table1.
It can just be a simple SQL function.
All of that put together:
CREATE or REPLACE FUNCTION my_func2(_row table1)
RETURNS SETOF table1 AS
'SELECT ($1).*' LANGUAGE sql;
Note the parentheses, which are essential for decomposing a row type. Per documentation:
The parentheses are required here to show that compositecol is a column name not a table name
But there is more ...
Don't use out as variable name, it's a keyword of the CREATE FUNCTION statement.
The syntax of your main query my_func() is more like psudo-code. Too much doesn't add up.
Proof of concept
Demo table:
CREATE TABLE table1(table1_id serial PRIMARY KEY, txt text);
INSERT INTO table1(txt) VALUES ('a'),('b'),('c'),('d'),('e'),('f'),('g');
Helper function:
CREATE or REPLACE FUNCTION my_func2(_row table1)
RETURNS SETOF table1 AS
'SELECT ($1).*' LANGUAGE sql;
Main function:
CREATE OR REPLACE FUNCTION my_func(int)
RETURNS SETOF table1 AS
$func$
DECLARE
rec table1;
BEGIN
FOR i IN 0..$1 LOOP
FOR rec IN
SELECT * FROM table1 WHERE table1_id = i
LOOP
RETURN QUERY
SELECT * FROM my_func2(rec);
END LOOP;
END LOOP;
END
$func$ LANGUAGE plpgsql;
Call:
SELECT * FROM my_func(99);
SQL Fiddle.
But it's really just a a proof of concept. Nothing useful, yet.
As the error log is telling you.. you can return only one column in a subquery, so you have to change it to
SELECT my_func2(SELECT Specific_column_you_need FROM hasval WHERE wid = i)
a possible solution can be that you pass to funct2 the primary key of the table your funct2 needs and then you can obtain the whole table by making the SELECT * inside the function
I have one function that returns all employee IDs
Function definition is like this:
CREATE OR REPLACE FUNCTION tmp()
RETURNS setof record AS
$func$
begin
select emp_id from employee_master;
end;
$func$
LANGUAGE plpgsql;
But when i call this function using
select * from tmp() as abc(emp_id text);
It gives error like
ERROR: query has no destination for result data
HINT: If you want to discard the results of a SELECT, use PERFORM instead.
CONTEXT: PL/pgSQL function "tmp" line 3 at SQL statement
Please give solution :)
If you want to return a rowset from a PL/PgSQL function you must use RETURN - in this case, probably RETURN QUERY:
RETURN QUERY SELECT emp_id FROM employee_master;
I don't see the point of having this in a PL/PgSQL function at all, though.
Make the function a plain SQL one as in:
...
LANGUAGE SQL;
It is much more practical to declare the actual type of the column instead of the unwieldy record type. Assuming emp_id to be integer, a simple SQL function could look like this:
CREATE OR REPLACE FUNCTION tmp()
RETURNS SETOF integer AS
$func$
SELECT emp_id FROM employee_master
$func$ LANGUAGE sql;
However, the error message in your comment does not match the given question. Depending on your actual requirements, you would adjust the RETURN type.
I have created a stored procedure / function with a simple SELECT in PostgreSQL:
CREATE FUNCTION select_proc2()
RETURNS SETOF procedure AS
$DELIMETER$
SELECT * FROM procedure;
$DELIMETER$
LANGUAGE 'sql'
This one works but when I tried to be specific like this:
CREATE FUNCTION select_proc2(INT)
RETURNS SETOF procedure AS
$DELIMETER$
SELECT "Fname" FROM procedure where "Id" = $1;
$DELIMETER$
LANGUAGE 'sql'
it returns an error:
ERROR: return type mismatch in function declared to return procedure
DETAIL: Final statement returns character instead of integer at
column 1. CONTEXT: SQL function "select_proc2"
I tried any solution that I can think of. Anyone here know how to solve this error?
You need to adapt the RETURN type to what's actually returned:
CREATE OR REPLACE FUNCTION select_proc2(int)
RETURNS SETOF text AS
$func$
SELECT "Fname" FROM procedure WHERE "Id" = $1;
$func$ LANGUAGE sql
In your second version you only return one column. From the name I am deriving the data type text, but that's just a guess.
If "Id" is the primary key column of procedure or otherwise defined UNIQUE, only one row can be returned and you can simplify to:
RETURNS text
Also don't quote the language name. sql is an identifier here, not a string literal. It's only tolerated for historic reason, but it's probably going to be an error in future versions.
Concerning your column names: My advise is to use non-quoted lower-case identifiers exclusively in Postgres. Start by reading the chapter "Identifiers and Key Words" to learn about the significance of "id", "Id", ID or id as column name.
remove quotes around field names (without "):
CREATE FUNCTION select_proc2(INT)
RETURNS SETOF procedure AS
$DELIMETER$
SELECT Fname FROM procedure where Id = $1;
$DELIMETER$
LANGUAGE 'sql'