using a plpgsql function argument as a table column.

2018-08-28 Thread ss
I have a table with many years as columns. y1976, y2077, .. , 
y2019,y2020 I want to dynamically return a column from a function.



select * from FUNCTION('y2016') .

select t1.cola t1.colb, t1.colc, t2.y2016 from . Where t2.y2016 != 0;

or if I select year y2012 I want FUNCTION('y2012')

select t1.cola t1.colb, t1.colc, t2.y2012 from . Where t2.y2012 != 0;


to generalize

select * from FUNCTION( year_column )

select t1.cola t1.colb, t1.colc, t2.year_column from . Where 
t2.year_column != 0;


is it possible? if so how?




Re: using a plpgsql function argument as a table column.

2018-08-28 Thread ss


CREATE OR REPLACE FUNCTION test(year VARCHAR)
RETURNS TABLE (agencycode INT, bureaucode INT, acctname VARCHAR, beacat 
VARCHAR, onoffbudget VARCHAR, val INT)

AS $$
BEGIN
RETURN QUERY SELECT t1.agencycode, t1.bureaucode, t1.acctcode, 
t2.beacat, t2.onoffbudget, t2.XX  FROM allnames AS t1
JOIN total AS t2 on t1.agencycode = t2.agencycode and t1.bureaucode = 
t2.bureaucode and t1.acctcode = t2.acctcode

WHERE t2.XXX != 0  ORDER BY t1.agencycode, t1.bureaucode, t1.acctcode;
END; $$
LANGUAGE 'plpgsql';

I want to replace XXX with the argument year.
I hard coded the XX with 'y2016' and I get back a table

Would something like 't2.'||(year)|| work?

On 08/28/2018 10:37 PM, Tim Cross wrote:
Off the top of my head, I think you could do this using dynamic 
(execute) SQL in a function. However, it is going to be messy, 
possibly slow and likely fragile. You would need to query the 
catalogue to get the column names in the table and then build the SQL 
dynamically 'on the fly'.


Without having more detail, my spider sense tells me you have the 
wrong table/relationship design. While you may be able to get it to 
work, it is likely you will run into constant problems and additional 
complexity that could be avoided with a different design. You really 
want a design where your queries are driven by the data in your tables 
and not by the names of columns. I would seriously consider 
re-examining your schema design, look at how your design fits in with 
the normal forms and adapt as necessary.


Tim

On Wed, 29 Aug 2018 at 15:10, ss <mailto:s...@tuxclub.org>> wrote:


I have a table with many years as columns. y1976, y2077, .. ,
y2019,y2020 I want to dynamically return a column from a function.


select * from FUNCTION('y2016') .

select t1.cola t1.colb, t1.colc, t2.y2016 from . Where
t2.y2016 != 0;

or if I select year y2012 I want FUNCTION('y2012')

select t1.cola t1.colb, t1.colc, t2.y2012 from . Where
t2.y2012 != 0;


to generalize

select * from FUNCTION( year_column )

select t1.cola t1.colb, t1.colc, t2.year_column from . Where
t2.year_column != 0;

is it possible? if so how?




--
regards,

Tim

--
Tim Cross





Re: using a plpgsql function argument as a table column.

2018-08-31 Thread ss

I changed the data from the years in one row to each row has a year

create table tvalues as
select t.key, year, value from values t
  join lateral (values
    (2021,t.y2021),
    (2020,t.y2020),
    (2019,t.y2019),
    (2018,t.y2018),
    (2017,t.y2017),
    (2016,t.y2016),
    (2015,t.y2015),
    (2014,t.y2014),
    (2013,t.y2013),
    (2012,t.y2012),
    (2011,t.y2011),
    (2010,t.y2010),
    (2009,t.y2009),
    (2008,t.y2008),
    (2007,t.y2007),
    (2006,t.y2006),
    (2005,t.y2005),
    (2004,t.y2004),
    (2003,t.y2003),
    (2002,t.y2002),
    (2001,t.y2001),
    (2000,t.y2000),
    (1999,t.y1999),
    (1998,t.y1998),
    (1997,t.y1997),
    (1996,t.y1996),
    (1995,t.y1995),
    (1994,t.y1994),
    (1993,t.y1993),
    (1992,t.y1992),
    (1991,t.y1991),
    (1990,t.y1990),
    (1989,t.y1989),
    (1988,t.y1988),
    (1987,t.y1987),
    (1986,t.y1986),
    (1985,t.y1985),
    (1984,t.y1984),
    (1983,t.y1983),
    (1982,t.y1982),
    (1981,t.y1981),
    (1980,t.y1980),
    (1979,t.y1979),
    (1978,t.y1979),
    (1977,t.y1977),
    (1976,t.y1976))
  s(year, value) ON TRUE;

On 08/29/2018 06:40 AM, Adrian Klaver wrote:

On 08/28/2018 10:40 PM, ss wrote:


CREATE OR REPLACE FUNCTION test(year VARCHAR)
RETURNS TABLE (agencycode INT, bureaucode INT, acctname VARCHAR, 
beacat VARCHAR, onoffbudget VARCHAR, val INT)

AS $$
BEGIN
RETURN QUERY SELECT t1.agencycode, t1.bureaucode, t1.acctcode, 
t2.beacat, t2.onoffbudget, t2.XX  FROM allnames AS t1
JOIN total AS t2 on t1.agencycode = t2.agencycode and t1.bureaucode = 
t2.bureaucode and t1.acctcode = t2.acctcode
WHERE t2.XXX != 0  ORDER BY t1.agencycode, t1.bureaucode, 
t1.acctcode;

END; $$
LANGUAGE 'plpgsql';

I want to replace XXX with the argument year.
I hard coded the XX with 'y2016' and I get back a table


So something along lines of:

DO $$
    DECLARE
    col_name varchar;
    out_str  varchar;
    BEGIN
    col_name = 'y'||'2018';
    out_str = format('SELECT %I FROM some_table where %I = 0', 
col_name, col_name );

    RAISE NOTICE '%', out_str;
    END;
$$ LANGUAGE plpgsql;


NOTICE:  SELECT y2018 FROM some_table where y2018 = 0



Would something like 't2.'||(year)|| work?

On 08/28/2018 10:37 PM, Tim Cross wrote:
Off the top of my head, I think you could do this using dynamic 
(execute) SQL in a function. However, it is going to be messy, 
possibly slow and likely fragile. You would need to query the 
catalogue to get the column names in the table and then build the 
SQL dynamically 'on the fly'.


Without having more detail, my spider sense tells me you have the 
wrong table/relationship design. While you may be able to get it to 
work, it is likely you will run into constant problems and 
additional complexity that could be avoided with a different design. 
You really want a design where your queries are driven by the data 
in your tables and not by the names of columns. I would seriously 
consider re-examining your schema design, look at how your design 
fits in with the normal forms and adapt as necessary.


Tim

On Wed, 29 Aug 2018 at 15:10, ss <mailto:s...@tuxclub.org>> wrote:


    I have a table with many years as columns. y1976, y2077, .. ,
    y2019,y2020 I want to dynamically return a column from a function.


    select * from FUNCTION('y2016') .

    select t1.cola t1.colb, t1.colc, t2.y2016 from . Where
    t2.y2016 != 0;

    or if I select year y2012 I want FUNCTION('y2012')

    select t1.cola t1.colb, t1.colc, t2.y2012 from . Where
    t2.y2012 != 0;


    to generalize

    select * from FUNCTION( year_column )

    select t1.cola t1.colb, t1.colc, t2.year_column from . Where
    t2.year_column != 0;

    is it possible? if so how?




--
regards,

Tim

--
Tim Cross