Alternate methods for multiple rows input/output to a function.

On 5/28/19 7:36 AM, RAJIN RAJ K wrote:

--> Function ' filter_id ' filters the ID's based on some conditions.
--> Input is set of ID's. (Not directly taking the input since there is
no provision to pass multiple rows to a function)

To be honest I cannot follow what you are trying to achieve below. I do
have one suggestion as to creating temp tables.

Why not use a CTE:

https://www.postgresql.org/docs/11/queries-with.html

in the function to build a 'temp' table on the fly?

create function filter_id()
return table (id bigint)
begin

--> Assuming input table is already created #temp_input_id

retun query as select id
from tbl a
inner join
#temp_input_id b on (a.id <http://a.id&gt; = b.id <http://b.id&gt;)
where a.<conditions>;

end;

--> Calling Function:

create function caller()
return table (id bigint,col1 bigint, col2 bigint)
begin

--> do some processing

--> Find out the input id's for filtering.

--> Create temp table for providing input for the filtering function

create temp table #TEMP1
as select id from tbla........;
(Cannot move the input id logic to  filter_function)

--> calling the filter function
create temp table #TEMP2
as select * from filter_id(); --> This is a generic function used in
many functions.

return query
as select a.*
from tb3 a inner join tb4 inner join tb 5 inner join #TEMP2;
end;

Is there any alternate way of achieving this? Passing multiple records
to a function im creating a temp table before invoking the function.
For receiving an output of multiple rows i'm creating a temp table to
reuse further in the code.

Can this be done using Refcursor? Is it possible to convert refcursor to
a temp table and use it as normal  table in query?

--
Adrian Klaver
adrian.klaver@aklaver.com

On 5/28/19 8:06 AM, RAJIN RAJ K wrote:

Please reply to list also.
Ccing list.

Thanks for the response.

CTE is not useful in my case. Here i want to pass the table to a
function and get the filtered results back from the function.
I tried few but not use full.
1. Pass table input --> Ref cursor is the only option but which again
require loop to fetch the records. (FETCH ALL results cannot be stored
in a variable)
    Here im creating temp table withe required input data before the
function call.

I'm going to take a stab at this though I do not entirely follow the
logic. Definitely not tested:

1) create function filter_id(tbl_name varchar)
return table (id bigint)
begin

--> Assuming input table is already created #temp_input_id

return query EXECUTE format('select id '
'from tbl a '
'inner join'
'%I b on (a.id = b.id)'
'where a.<conditions>', tbl_name);

end;

2) In calling function:

WITH temp_tbl AS (select id from tbla...
), filter_tbl AS (select * from filter_id(temp_bl))
select a.*
from tb3 a inner join tb4 inner join tb 5 inner join filter_tbl;

On Tue, May 28, 2019 at 8:29 PM Adrian Klaver <adrian.klaver@aklaver.com
<mailto:adrian.klaver@aklaver.com>> wrote:

On 5/28/19 7:36 AM, RAJIN RAJ K wrote:

--> Function ' filter_id ' filters the ID's based on some conditions.
--> Input is set of ID's. (Not directly taking the input since

there is

no provision to pass multiple rows to a function)

To be honest I cannot follow what you are trying to achieve below. I do
have one suggestion as to creating temp tables.

Why not use a  CTE:

https://www.postgresql.org/docs/11/queries-with.html

in the function to build a 'temp' table on the fly?

create function filter_id()
return table (id bigint)
begin

--> Assuming input table is already created #temp_input_id

retun query as select id
from tbl a
inner join
#temp_input_id b on (a.id <http://a.id&gt; <http://a.id&gt; = b.id

<http://b.id&gt; <http://b.id&gt;)

where a.<conditions>;

end;

--> Calling Function:

create function caller()
return table (id bigint,col1 bigint, col2 bigint)
begin

--> do some processing

--> Find out the input id's for filtering.

--> Create temp table for providing input for the filtering function

create temp table #TEMP1
as select id from tbla........;
(Cannot move the input id logic to  filter_function)

--> calling the filter function
create temp table #TEMP2
as select * from filter_id(); --> This is a generic function used in
many functions.

return query
as select a.*
from tb3 a inner join tb4 inner join tb 5 inner join #TEMP2;
end;

Is there any alternate way of achieving this? Passing multiple

records

to a function im creating a temp table before invoking the function.
For receiving an output of multiple rows i'm creating a temp

table to

reuse further in the code.

Can this be done using Refcursor? Is it possible to convert

refcursor to

a temp table and use it as normal  table in query?

--
Adrian Klaver
adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>

--
Adrian Klaver
adrian.klaver@aklaver.com