CREATE OR REPLACE FUNCTION test(year VARCHAR)
RETURNS TABLE (agencycode INT, bureaucode INT, acctname VARCHAR, beacat VARCHAR, onoffbudget VARCHAR, val INT)
AS $$
BEGIN
RETURN QUERY SELECT t1.agencycode, t1.bureaucode, t1.acctcode, t2.beacat, t2.onoffbudget, t2.XXXXXX FROM allnames AS t1
JOIN total AS t2 on t1.agencycode = t2.agencycode and t1.bureaucode = t2.bureaucode and t1.acctcode = t2.acctcode
WHERE t2.XXXXXXX != 0 ORDER BY t1.agencycode, t1.bureaucode, t1.acctcode;
END; $$
LANGUAGE 'plpgsql';
I want to replace XXXXXXX with the argument year.
I hard coded the XXXXXX 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
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?
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