Basically i want to split the string based on the delimiter for example :-
"this,is,foo" should return this is foo i.e; without the comma into separate records .
i am trying to use pgadmin 4 version 2.
this is my sample code below that i want in function dialog :-
create or replace function STRING_SPLIT(str text,delimiter character)
return SET OF record;
as
begin
return QUERY SELECT trim(a)
FROM unnest(string_to_array('john,smith,jones', ',')) AS a; //str, delim
end
i am basically trying to insert the expanded row array into set of records.
i tried creating table and return it in the return statement but could not specify the column name in function dialog of pgadmin also i could not find "set of record" return type in the same dialog box?
can anyone help?
In almost all cases, using returns table() is the better solution.
create or replace function STRING_SPLIT(str text,delimiter character)
return table(word text) --<< no ; here!!
as
$$ --<< you need quotes around the body
SELECT trim(a) as word
FROM unnest(string_to_array(text, delimiter)) AS t(a);
$$
language sql; --<< no PL/pgSQL required, SQL is enough
If you do want to use setof record then you always have to specify the column names when using the function:
create or replace function STRING_SPLIT(str text,delimiter character)
return setof record
as
$$ --<< you need quotes around the body
SELECT trim(a) as word
FROM unnest(string_to_array(text, delimiter)) AS t(a);
$$
language sql; --<< no PL/pgSQL required, SQL is enough
Then:
select *
from string_split('foo,bar',',') as t(word);
However, Postgres already has a built-in function for this:
select *
from regexp_split_to_table('foo,bar',',') as t(word);
Though this post is older, but needs to post an answer here. So it will help people like me. As I was looking for the same and found the answer.
in pgAdmin4 'setof' is not present in the return type. While creating function in pgAdmin using create function window, you need to select record as a return type.
Then click on the options and set "Returns a set?" to "Yes". like this
Then it will automatically take setof record as a return type and will show in code in sql viwer, but not in return type selected.
Then it will automatically take setof record as a return type and will show in code in sql viwer, but not in return type selected.
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.
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 would like to execute a SQL statement based on a string. I have created the SQL statement through a function which returns a string. Can anybody explain how I can execute the statement that is returned? I know that you can't do it in plain SQL, so I was thinking about putting it in a function. The only issue is that the columns in the statement aren't always the same, so I don't know which data types to use for the columns. I'm using Postgres 9.1.0.
For example, suppose the SQL string returned from my function the is:
Select open, closed, discarded from abc
But, it can also be:
Select open from abc
Or
Select open, closed from abc
How can I execute any of these strings, so that the results would be returned as a table with only the columns listed in the statement?
Edit: the function is written in PL/pgSQL. And the results will be used for reporting where they don't want to see columns that have no values. So the function that I wrote returns the names of all columns that have values and then add it to the SQL statement.
Thanks for your help!
I don't think you can return the rows directly from a function, because its return type would be unknown. Even if you specified the return type as RECORD, you'd have to list the returned columns at call time. Based on Wayne Conrad's idea, you could do this:
CREATE FUNCTION my_create(cmd TEXT) RETURNS VOID AS $$
BEGIN
EXECUTE 'CREATE TEMPORARY TABLE temp_result AS ' || cmd;
END;
$$ VOLATILE LANGUAGE plpgsql;
Then use the function like this:
BEGIN;
SELECT my_create(...);
SELECT * FROM temp_result;
ROLLBACK; -- or COMMIT
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'