How can I iterate over integer[] if I have:
operators_ids = string_to_array(operators_ids_g,',')::integer[];
I want iterate over operators_ids.
I can't do it in this way:
FOR oid IN operators_ids LOOP
and this:
FOR oid IN SELECT operators_ids LOOP
oid is integer;
You can iterate over an array like
DO
$body$
DECLARE your_array integer[] := '{1, 2, 3}'::integer[];
BEGIN
FOR i IN array_lower(your_array, 1) .. array_upper(your_array, 1)
LOOP
-- do something with your value
raise notice '%', your_array[i];
END LOOP;
END;
$body$
LANGUAGE plpgsql;
But the main question in my view is: why do you need to do this? There are chances you can solve your problem in better ways, for example:
DO
$body$
DECLARE i record;
BEGIN
FOR i IN (SELECT operators_id FROM your_table)
LOOP
-- do something with your value
raise notice '%', i.operators_id;
END LOOP;
END;
$body$
LANGUAGE plpgsql;
I think Dezso is right. You do not need to use looping the array using an index.
If you make a select statement grouping by person_id in combination with limit 1, you have the result set you wanted:
create or replace function statement_example(p_data text[]) returns int as $$
declare
rw event_log%rowtype;
begin
for rw in select * from "PRD".events_log where (event_type_id = 100 or event_type_id = 101) and person_id = any(operators_id::int[]) and plc_time < begin_date_g order by plc_time desc group by person_id limit 1 loop
raise notice 'interesting log: %', rw.field;
end loop;
return 1;
end;
$$ language plpgsql volatile;
That should perform much better.
If you still prefer looping an integer array and there are a lot of person_ids to look after, then might you consider using the flyweight design pattern:
create or replace function flyweight_example(p_data text[]) returns int as $$
declare
i_id int;
i_min int;
i_max int;
begin
i_min := array_lower(p_data,1);
i_max := array_upper(p_data,1);
for i_id in i_min .. i_max loop
raise notice 'interesting log: %',p_data[i_id];
end loop;
return 1;
end;
$$ language plpgsql volatile;
Related
I am trying to assign a variable the result of a query in a postgres stored procedure.
Here is what I am trying to run:
CREATE OR Replace PROCEDURE schema.MyProcedure()
AS $$
DECLARE
RowCount int = 100;
BEGIN
select cnt into RowCount
from (
Select count(*) as cnt
From schema.MyTable
) ;
RAISE NOTICE 'RowCount: %', RowCount;
END;
$$
LANGUAGE plpgsql;
schema.MyTable is just some arbitrary table name but the script is not displaying anything, not even the random value I assigned RowCount to (100).
What am I doing wrong?
Thanks
You need an alias for the subquery, for example : as sub
CREATE OR Replace PROCEDURE schema.MyProcedure()
AS $$
DECLARE
RowCount int = 100;
BEGIN
select cnt into RowCount
from (
Select count(*) as cnt
From schema.MyTable
) as sub ;
RAISE NOTICE 'RowCount: %', RowCount;
END;
$$
LANGUAGE plpgsql;
You can also assign any variable with a query result in parenthesis.
CREATE OR REPLACE PROCEDURE schema.my_procedure()
AS
$$
DECLARE
row_count BIGINT;
BEGIN
row_count = (SELECT COUNT(*) FROM schema.my_table);
RAISE NOTICE 'RowCount: %', row_count;
END;
$$ LANGUAGE plpgsql;
You should use BIGINT instead of INT.
And it's far better to write your code and table definition with snake_case style as possible.
I am trying to run the code:
CREATE OR REPLACE FUNCTION anly_work_tbls.testfncjh (tablename text) returns int
AS $$
DECLARE
counter int;
rec record;
tname text;
BEGIN
counter = 0;
tname := tablename;
FOR rec IN
select *
from tname
loop
counter = counter + 1;
end loop;
RETURN counter;
END;
$$
LANGUAGE 'plpgsql' IMMUTABLE
SECURITY DEFINER;
The goal of this code is to return the number of rows in the table you input. I know that this might not be the best way to accomplish this task, but the structure of this function would extend nicely to another question I am trying to tackle. Every time I run the code, I get the error:
ERROR: syntax error at or near "$1"
All online resources I have found tell me how to use the input variable within and EXECUTE block, but not in the above situation.
Currently running PostgreSQL 8.2.15.
CREATE OR REPLACE FUNCTION anly_work_tbls.testfncjh (tbl regclass, OUT row_ct int) AS
$func$
BEGIN
EXECUTE 'SELECT count(*) FROM '|| tbl
INTO row_ct;
END
$func$ LANGUAGE plpgsql IMMUTABLE SECURITY DEFINER;
Call:
SELECT anly_work_tbls.testfncjh('anly_work_tbls.text_tbl');
This should work for Postgres 8.2, but you consider upgrading to a current version anyway.
I pass the table name as object identifier type regclass, which takes care of quoting automatically and works with schema-qualified names. Details:
Table name as a PostgreSQL function parameter
Using an OUT parameter simplifies the function.
Don't quote the language name. It's an identifier.
If you actually need to loop through the result of a dynamic query:
CREATE OR REPLACE FUNCTION anly_work_tbls.testfncjh (tbl regclass)
RETURNS int AS
$func$
DECLARE
counter int := 0; -- init at declaration time
rec record;
BEGIN
FOR rec IN EXECUTE
'SELECT * FROM ' || tbl
LOOP
counter := counter + 1; -- placeholder for some serious action
END LOOP;
RETURN counter;
END
$func$ LANGUAGE plpgsql IMMUTABLE SECURITY DEFINER;
Read this chapter in the manual: Looping Through Query Results
The documented assignment operator in plpgsql is :=:
The forgotten assignment operator "=" and the commonplace ":="
Yes is really not the best way, but this would work:
CREATE OR REPLACE FUNCTION testfncjh (tablename text) returns int
AS $$
DECLARE
counter int;
rec record;
BEGIN
counter = 0;
FOR rec IN
EXECUTE 'select * from '||quote_ident(tablename) loop
counter = counter + 1;
end loop;
RETURN counter;
END;
$$
LANGUAGE 'plpgsql' IMMUTABLE
SECURITY DEFINER;
This would be nicer:
CREATE OR REPLACE FUNCTION testfncjh (tablename text) returns int
AS $$
DECLARE _count INT;
BEGIN
EXECUTE 'SELECT count(*) FROM '|| quote_ident(tablename) INTO _count;
RETURN _count;
END;
$$
LANGUAGE 'plpgsql' IMMUTABLE
SECURITY DEFINER;
I have a plpgslq function which does some data processing and would like to write a for loop, however my table name is not known at design time. Is there any possible way to achieve this? Here is sample code snippet of what I want to achieve:
-- Function: check_data()
-- DROP FUNCTION check_data();
CREATE OR REPLACE FUNCTION check_data()
RETURNS character varying AS
$BODY$declare
dyn_rec record;
tbl_name record;
begin
-- sample dynamic tables
tbl_name := 'cars';
tbl_name := 'trucks';
tbl_name := 'bicycles';
for dyn_rec in select * from format($$s%$$,tbl_name) loop
raise notice 'item is %',dyn_rec.item_no;
end loop;
return 'Processing Ok';
end;$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION check_data()
OWNER TO postgres;
You cannot use a variable as table or column identifier in plpgsql embedded SQL ever. A solution is dynamic SQL - EXECUTE or FOR IN EXECUTE statements:
DO $$
DECLARE
tables text[] = ARRAY['table1','table2'];
table_name text;
rec record;
BEGIN
FOREACH table_name IN ARRAY tables
LOOP
FOR r IN EXECUTE format('SELECT * FROM %I', table_name)
LOOP
RAISE NOTICE '%', rec;
END LOOP;
END LOOP;
END; $$
Just like the below function. I don't know how to return a set of inside parameter in postgresql?
create or replace function g_i(num int)
returns setof integer
as $$
declare
i int;
begin
while i < $1 loop
select i; -- How to write statements here?
end loop;
end;
$$ language plpgsql;
create or replace function g_i(num int)
returns setof integer
as $$
declare
i int;
begin
i := 0;
while i< $1 loop
i := i+1;
return query select i;
end loop;
end;
$$ language plpgsql;
I am new to PostgreSQL and have a simple task with a looping structure.
Trying to print 0 to 10. Here is my function:
CREATE OR REPLACE FUNCTION LOOPING()
RETURNS TABLE(asd text) AS
$BODY$declare
i integer;
Begin
i:=0;
WHILE i > 10 LOOP
select i;
i:=(i+1);
END LOOP;
end;$BODY$
LANGUAGE plpgsql IMMUTABLE
COST 100
ROWS 1000;
ALTER FUNCTION LOOPING()
OWNER TO postgres;
I have tried with while loop. If anybody can do this task with for loop it will be very helpful.
You have several hick-ups in there. One working way (of many):
CREATE OR REPLACE FUNCTION f_loop()
RETURNS TABLE(asd int) AS
$BODY$
BEGIN
asd := 0;
WHILE asd < 11 LOOP
RETURN NEXT;
asd := asd + 1;
END LOOP;
END
$BODY$ LANGUAGE plpgsql IMMUTABLE
Call:
SELECT * FROM f_loop();
FOR loop
CREATE OR REPLACE FUNCTION f_loop()
RETURNS TABLE(asd int) AS
$BODY$
BEGIN
FOR i IN 0..10 LOOP
asd := i;
RETURN NEXT;
END LOOP;
END
$BODY$ LANGUAGE plpgsql IMMUTABLE;
Or, for this simple case:
CREATE OR REPLACE FUNCTION f_loop()
RETURNS SETOF int AS
$BODY$
BEGIN
FOR i IN 0..10 LOOP
RETURN NEXT i;
END LOOP;
END
$BODY$ LANGUAGE plpgsql IMMUTABLE;
Details in the excellent manual.
Your problem as far as I can see is that you have to return the value properly and RETURN NEXT in my experiments (on Pg 9.1) did not work as I expected it to.
I tested this and it was working:
create or replace function loop() returns table (i int)
language plpgsql as
$$
declare i_array int[];
begin
for i in 0 .. 10 loop
i_array := i_array || i;
end loop;
return query select unnest(i_array);
end;
$$;