I am writing a Postgres function to get the number of new records in a table. Here table name is a variable.
create or replace function dmt_mas_updates(
tb_name text,
days integer)
returns integer as
$$
declare
ct integer;
begin
execute 'select count(*) from $1 where etl_create_dtm > now() - $2 * interval ''1 days'' '
using tb_name, days into ct;
return ct;
end;
$$ LANGUAGE 'plpgsql'
When I call the function with select * from dmt_mas_updates('dmt_mas_equip_store_dim',2);, I got syntax error at $1.
If I run the query directly select count(*) from dmt_mas_equip_store_dim where etl_create_dtm >= interval '3 days', it works correctly.
Why am I getting this error? What did I do wrong?
Per the documentation:
Note that parameter symbols can only be used for data values — if you want to use dynamically determined table or column names, you must insert them into the command string textually.
Use the format() function:
create or replace function dmt_mas_updates(
tb_name text,
days integer)
returns integer as
$$
declare
ct integer;
begin
execute format(
'select count(*) from %I where etl_create_dtm > now() - $1 * interval ''1 days'' ',
tb_name)
using days into ct;
return ct;
end;
$$ LANGUAGE 'plpgsql';
Related
I have a database function as below:
drop function test(month_interval text)
create or replace function test (month_interval text) returns date as
$$
select ('2020-07-01'::date - interval month_interval)::date;
$$ language sql;
select * from test('2 months')
I have a scenario where I want to dynamically compute month intervals and want to have one database query that can be used by passing month intervals as function parameters. However when i do this it gives me the following error :
ERROR: syntax error at or near "month_interval"
You could cast the text to an interval:
create or replace function test (month_interval text) returns date as
$$
select ('2020-07-01'::date - month_interval::interval)::date;
$$ language sql;
select test('2 months');
But why not pass an interval directly?
create or replace function test (month_interval interval) returns date as
$$
select ('2020-07-01'::date - month_interval)::date;
$$ language sql;
select test(interval '2 months');
Alternatively you can pass the number of months, then use make_interval:
create or replace function test (num_months int) returns date as
$$
select ('2020-07-01'::date - make_interval(months => num_months))::date;
$$ language sql;
select test(2);
I have a sql query where I want to extract records older than 'X' number of days, here for eg its 7 days:
SELECT * FROM BOOKMARK.MONITORING_TABLE WHERE inserteddatetime < (now() - '7 day'::interval);
I have to execute this query through a stored procedure passing in the configurable 'X' no of days as arguments.
The procedure is as below:
CREATE OR REPLACE FUNCTION DELETE_REDUNDANT_RECORDS_STORED_PROCEDURE(days int)
RETURNS void AS
$func$
DECLARE
rec_old RECORD;
cursor_data CURSOR FOR
SELECT * FROM BOOKMARK.MONITORING_TABLE WHERE inserteddatetime < now() - '$1 day'::interval;
BEGIN
OPEN cursor_data;
// business logic for the procedure
CLOSE cursor_data;
END;
$func$
LANGUAGE plpgsql;
This doesn't work as I am not able to use the placeholder for days in my query. How do we use the arguments passed to my query in this case.
To create an interval based on an integer, make_interval() is much easier to use than casting to an interval type.
Additional I wouldn't use a cursor, but a FOR loop based on a SELECT statement (maybe using make_interval(days => $1) works in the cursor declaration as well)
CREATE OR REPLACE FUNCTION DELETE_REDUNDANT_RECORDS_STORED_PROCEDURE(days int)
RETURNS void AS
$func$
DECLARE
rec_old record;
BEGIN
for rec_old in SELECT *
FROM BOOKMARK.MONITORING_TABLE
WHERE inserteddatetime < now() - make_interval(days => $1)
loop
raise notice 'records %', rec_old;
end loop;
END;
$func$
LANGUAGE plpgsql;
How to pass a parameter in crosstab query in postgresql.
Please refer the below function in postgresql
create function sp_nextfollowup_count_byweek(_from timestamp without time zone,_to timestamp without time zone)
returns table(userid integer,username character varying,day1 bigint,day2 bigint,day3 bigint,day4 bigint,day5 bigint,day6 bigint,day7 bigint)as
$BODY$
BEGIN
return query
with cte as(
select * from crosstab($$
select follow_up_by,next_follow_up_date,count(*) from sales_enquiry_follow_up where next_follow_up_date between _from and _to
group by follow_up_by,next_follow_up_date
order by follow_up_by,next_follow_up_date$$,$$select date::timestamp without time zone
from generate_series(
_from,
_to,
'1 day'::interval
) date$$)
as(id integer, dd bigint,dd1 bigint,dd2 bigint,dd3 bigint,dd4 bigint,dd5 bigint,dd6 bigint)
)
select cte.id,u.username,cte.dd,cte.dd1,cte.dd2,cte.dd3,cte.dd4,cte.dd5,cte.dd6 from cte left join users u on cte.id=u.id;
END;
$BODY$
language plpgsql;
I am getting this error column "_from" does not exist. How to solve this issue?
Because argument of crosstab is just string you must include arguments directly:
$$
select follow_up_by,next_follow_up_date,count(*) from sales_enquiry_follow_up where next_follow_up_date between $$ || quote_literal(_from) || $$ and $$ || quote_literal(_to) || $$
group by follow_up_by,next_follow_up_date
order by follow_up_by,next_follow_up_date$$
I have the following table with one field of type timestamp.
Create table Test_Timestamp
(
ColumnA timestamp
);
Now inserting some records for demonstration:
INSERT INTO Test_Timestamp VALUES('1900-01-01 01:21:15'),
('1900-01-01 02:11:25'),
('1900-01-01 12:52:10'),
('1900-01-01 03:20:05');
Now I have created function Function_Test with two parameters namely St_time and En_Time which
are of type varchar, In which I only pass the time like 00:00:01. And after that Function has
to return the table with that condition of two time's parameters.
CREATE OR REPLACE FUNCTION Function_Test
(
St_Time varchar,
En_Time varchar
)
RETURNS TABLE
(
columX timestamp
)
AS
$BODY$
Declare
sql varchar;
wher varchar;
BEGIN
wher := 'Where columna BETWEEN '|| to_char(cast(St_Time as time),'''HH24:MI:SS''') ||' AND '|| to_char(cast(En_Time as time),'''HH24:MI:SS''') ||'';
RAISE INFO '%',wher;
sql := 'SELECT * FROM Test_Timestamp ' || wher ;
RAISE INFO '%',sql;
RETURN QUERY EXECUTE sql;
END;
$BODY$
LANGUAGE PLPGSQL;
---Calling function
SELECT * FROM Function_Test('00:00:00','23:59:59');
But getting an error:
ERROR: invalid input syntax for type timestamp: "00:00:01"
LINE 1: ...ELECT * FROM Test_Timestamp where ColumnA BETWEEN '00:00:01'...
You can cast the column to a time: ColumnA::time
You should also not pass a time (or a date, or a timestamp) as a varchar. And you don't need dynamic SQL or a PL/pgSQL function for this:
CREATE OR REPLACE FUNCTION Function_Test(St_Time time, en_Time time)
RETURNS TABLE (columX timestamp)
AS
$BODY$
SELECT *
FROM Test_Timestamp
where columna::time between st_time and en_time;
$BODY$
LANGUAGE sql;
Call it like this:
select *
from Function_Test(time '03:00:00', time '21:10:42');
You can use extract to the hour, minute and second
http://www.postgresql.org/docs/9.3/static/functions-datetime.html#FUNCTIONS-DATETIME-EXTRACT
How can I use:
select * from <some_table>;
in a FUNCTION in Postgres?
CREATE OR REPLACE FUNCTION my_function() RETURNS INTEGER AS '
DECLARE
your_record your_table%ROWTYPE;
BEGIN
FOR your_record IN SELECT * FROM your_table
LOOP
--
-- You can access fields of your table using .
-- your_record.your_field
...
END LOOP;
END;
' LANGUAGE 'plpgsql'
STABLE;
or
CREATE OR REPLACE FUNCTION my_function() RETURNS INTEGER AS '
DECLARE
your_record your_table%ROWTYPE;
BEGIN
SELECT * INTO your_record FROM your_table;
--
-- You can access fields of your table using .
-- your_record.your_field
END;
' LANGUAGE 'plpgsql'
STABLE;
EDIT:
With join returning a record:
CREATE OR REPLACE FUNCTION my_function() RETURNS SETOF record AS '
DECLARE
your_record record;
BEGIN
--
-- You should specify a list of fields instead of *
--
FOR your_record IN SELECT * FROM your_table INNER JOIN ...
RETURN NEXT your_record;
END LOOP;
END;
' LANGUAGE 'plpgsql'
STABLE;
To use my_function(), you have to specify fields and datatypes:
See details here
There is a smipler method, if you want to use SQL in the function, use SQL language in the function:
CREATE FUNCTION getallzipcodes()
RETURNS SETOF zip AS
$BODY$
SELECT * FROM zip;
$BODY$
LANGUAGE 'sql';
And this might be useful too (how to call the function)
SELECT function_returning_setof(); -- Wrong!
SELECT * FROM function_returning_setof(); -- OK!
SELECT function_returning_scalar(); -- OK
reference