Store the result of sql and process it in informix - informix

Question

We have a view which contains 2 columns: pattern_start_time, pattern_end_time.
The select query in the function will convert it to minutes and using that result we are processing to get the shift unused coverage.The function is getting created but the processing is not happening and getting the below error:
SQLError[IX000]:Routine (my_list) cant be resolved.
Also please enter image description heresuggest to loop till the length of the result.
CREATE function myshifttesting(orgid int) returning int;
DEFINE my_list LIST( INTEGER not null );
DEFINE my_list1 LIST( INTEGER not null );
define i, j, sub, sub1 int;
define total int;
TRACE ON;
TRACE 'my testing starts';
INSERT INTO TABLE( my_list )
select
((extend(current, year to second) + (dots.v_shift_coverage.pattern_start_time - datetime(00:00) hour to minute) - current)::interval minute(9) to minute)::char(10)::INTEGER
from
dots.v_shift_coverage
where
org_guid = orgid;
INSERT INTO TABLE( my_list1 )
select
((extend(current, year to second) + (dots.v_shift_coverage.pattern_end_time - datetime(00:00) hour to minute) - current)::interval minute(9) to minute)::char(10)::INTEGER
from
dots.v_shift_coverage
where
org_guid = orgid;
let sub = 0;
let sub1 = 0;
let total = 0;
for j = 0 to 4
if (my_list(j) < my_list1(j))
then
if (my_list(j + 1) > my_list1(j))
then
let sub = sub + my_list(j + 1) - my_list1(j);
end if;
end if;
end for
if (my_list(0) > my_list1(4))
then
let sub1 = my_list(0) - my_list1(4);
end if;
let total = sub + sub1;
return total;
end function;

Answer 1

The error that you are receiving is because my_list(j) is not valid Informix syntax to access a LIST element. Informix is interpreting my_list(j) as a call to a function named mylist.
You can use a temporary table to "emulate" an array with your logic, something like this:
CREATE TABLE somedata
(
letter1 CHAR( 2 ),
letter2 CHAR( 2 )
);
INSERT INTO somedata VALUES ( 'a1', 'a2' );
INSERT INTO somedata VALUES ( 'b1', 'b2' );
INSERT INTO somedata VALUES ( 'c1', 'c2' );
INSERT INTO somedata VALUES ( 'd1', 'd2' );
INSERT INTO somedata VALUES ( 'e1', 'e2' );
DROP FUNCTION IF EXISTS forloop;
CREATE FUNCTION forloop()
RETURNING CHAR( 2 ) AS letter1, CHAR( 2 ) AS letter2;
DEFINE number_of_rows INTEGER;
DEFINE iterator INTEGER;
DEFINE my_letter1 CHAR( 2 );
DEFINE my_letter2 CHAR( 2 );
-- Drop temp table if it already exists in the session
DROP TABLE IF EXISTS tmp_data;
CREATE TEMP TABLE tmp_data
(
tmp_id SERIAL,
tmp_letter1 CHAR( 2 ),
tmp_letter2 CHAR( 2 )
);
-- Insert rows into the temp table, serial column will be the access key
INSERT INTO tmp_data
SELECT 0,
d.letter1,
d.letter2
FROM somedata AS d
ORDER BY d.letter1;
-- Get total rows of temp table
SELECT COUNT( * )
INTO number_of_rows
FROM tmp_data;
FOR iterator = 1 TO number_of_rows
SELECT d.tmp_letter1
INTO my_letter1
FROM tmp_data AS d
WHERE d.tmp_id = iterator;
-- Check if not going "out of range"
IF iterator < number_of_rows THEN
SELECT d.tmp_letter2
INTO my_letter2
FROM tmp_data AS d
WHERE d.tmp_id = iterator + 1;
ELSE
-- iterator + 1 is "out of range", return to the beginning
SELECT d.tmp_letter2
INTO my_letter2
FROM tmp_data AS d
WHERE d.tmp_id = 1;
END IF;
RETURN my_letter1, my_letter2 WITH RESUME;
END FOR;
END FUNCTION;
-- Running the function
EXECUTE FUNCTION forloop();
-- Results
letter1 letter2
a1 b2
b1 c2
c1 d2
d1 e2
e1 a2
5 row(s) retrieved.