Package compilation fails with ORA-00927: missing equal sign - oracle

Question

I am creating a package and I don't understand why the error occurs.
My package:
create or replace PACKAGE test_action AS
subj CHAR default '';
count_student INTEGER default 0;
FUNCTION count_positive(subject CHAR) RETURN INTEGER;
PROCEDURE number_requests;
END test_action;
Package body:
CREATE OR REPLACE PACKAGE BODY test_action AS
FUNCTION count_positive(sub CHAR) RETURN INTEGER
AS
BEGIN
count_student := 0;
subj := sub;
SELECT COUNT(*) INTO count_student
FROM D8_EXAMS E JOIN D8_SUBJECT S
ON E.subj_id = S.subj_id
WHERE E.mark > 3 AND S.subj_name = subject
GROUP BY S.subj_name;
number_requests;
return count_student;
END count_positive;
PROCEDURE number_requests AS
BEGIN
INSERT INTO package_table (subject,counts,callCount)
VALUES (subj,count_student,1);
exception
when dup_val_on_index then
update t
set callCount := callCount + 1,
set counts := count_student
where subject = subj;
END number_requests;
END test_action;
and then I get an error
if I try to add assignment to variables before the function description, then a new error occurs

Answer 1

Because - as error says - you're missing equal sign (it is just =, not :=), and there's only one set keyword per update:
update t
set callCount = callCount + 1,
counts = count_student
where subject = subj;
Apart from that:
function declaration in package body must match the one in package specification
in exception, you're updating table t; shouldn't that be package_table?
select count(*) has group by clause; to me, it smells like possible point to raise too_many_rows error you didn't handle
This, at least, compiles: package spec:
SQL> CREATE OR REPLACE PACKAGE test_action
2 AS
3 subj CHAR DEFAULT '';
4 count_student INTEGER DEFAULT 0;
5
6 FUNCTION count_positive (sub CHAR)
7 RETURN INTEGER;
8
9 PROCEDURE number_requests;
10 END test_action;
11 /
Package created.
Package body:
SQL> CREATE OR REPLACE PACKAGE BODY test_action
2 AS
3 FUNCTION count_positive (sub CHAR)
4 RETURN INTEGER
5 AS
6 BEGIN
7 count_student := 0;
8 subj := sub;
9
10 SELECT COUNT (*)
11 INTO count_student
12 FROM D8_EXAMS E JOIN D8_SUBJECT S ON E.subj_id = S.subj_id
13 WHERE E.mark > 3
14 AND S.subj_name = sub
15 GROUP BY S.subj_name;
16
17 number_requests;
18 RETURN count_student;
19 END count_positive;
20
21 PROCEDURE number_requests
22 AS
23 BEGIN
24 INSERT INTO package_table (subject, counts, callCount)
25 VALUES (subj, count_student, 1);
26 EXCEPTION
27 WHEN DUP_VAL_ON_INDEX
28 THEN
29 UPDATE package_table
30 SET callCount = callCount + 1, counts = count_student
31 WHERE subject = subj;
32 END number_requests;
33 END test_action;
34 /
Package body created.
SQL>