Oracle: How to wrap a Cursor inside A Function? - sql

Question

I am working on an assignment and it requires me to place a cursor inside a function.
Now my cursor works fine, but I am having a hard time placing it inside a a function, how can I do this?
The function is supposed to have the same argument as the cursor.
Code:
DECLARE
CURSOR c_emp_salary (v_job_title VARCHAR2)
IS
SELECT employee_id, first_name, salary, min_salary FROM employees e JOIN jobs j ON
e.job_id = j.job_id
AND j.job_title = v_job_title;
v_emp_id employees.employee_id%TYPE;
v_emp_first_name employees.first_name%TYPE;
v_emp_salary employees.salary%TYPE;
v_min_salary jobs.min_salary%TYPE;
BEGIN
OPEN c_emp_salary('Shipping Clerk'); --I WANT THIS VALUE TO BE FROM A FUNCTION.
LOOP
FETCH c_emp_salary INTO v_emp_id, v_emp_first_name, v_emp_salary, v_min_salary;
EXIT WHEN c_emp_salary%NOTFOUND;
dbms_output.put_line('Employee ID: ' || v_emp_id);
dbms_output.put_line('Employee First Name: ' || v_emp_first_name);
dbms_output.put_line('Employee Salary: ' || v_emp_salary);
dbms_output.put_line('Job Min Salary: ' || v_min_salary);
dbms_output.put('Result? ');
IF v_emp_salary = v_min_salary THEN dbms_output.put('Yes');
ELSE dbms_output.put('No');
END IF;
dbms_output.put_line(NULL);
dbms_output.put_line('++++++++++++++++++++++++');
END LOOP;
END;
The assignment description: Write a function that takes job_title and checks all employees in
that job, if an employee has salary equal to min_salary print
“yes” else print “no”. Use a cursor

Answer 1

"Use a cursor" is pointless because every DML or SELECT statement is a cursor.
Anyway, I assume you are looking for this:
CREATE OR REPLACE FUNCTION WRITE_SALARY(v_job_title IN VARCHAR2) AS
CURSOR c_emp_salary IS
SELECT employee_id, first_name, salary, min_salary
FROM employees e
JOIN jobs j ON e.job_id = j.job_id
WHERE j.job_title = v_job_title;
v_emp_id employees.employee_id%TYPE;
v_emp_first_name employees.first_name%TYPE;
v_emp_salary employees.salary%TYPE;
v_min_salary jobs.min_salary%TYPE;
BEGIN
OPEN c_emp_salary;
...

Answer 2

I assume you need something as:
(It needed substitute SCHEMA_NAME and FUNCTION_NAME)
(If return does not needed procedure can be used, and return statements should be removed)
(I don't run this example)
CREATE OR REPLACE function SCHEMA_NAME.FUNCTION_NAME( v_job_title VARCHAR2) return number is
CURSOR c_emp_salary
IS
SELECT employee_id, first_name, salary, min_salary FROM employees e JOIN jobs j ON
e.job_id = j.job_id
AND j.job_title = v_job_title;
v_emp_id employees.employee_id%TYPE;
v_emp_first_name employees.first_name%TYPE;
v_emp_salary employees.salary%TYPE;
v_min_salary jobs.min_salary%TYPE;
result number;
BEGIN
OPEN c_emp_salary('Shipping Clerk'); --I WANT THIS VALUE TO BE FROM A FUNCTION.
LOOP
FETCH c_emp_salary INTO v_emp_id, v_emp_first_name, v_emp_salary, v_min_salary;
EXIT WHEN c_emp_salary%NOTFOUND;
dbms_output.put_line('Employee ID: ' || v_emp_id);
dbms_output.put_line('Employee First Name: ' || v_emp_first_name);
dbms_output.put_line('Employee Salary: ' || v_emp_salary);
dbms_output.put_line('Job Min Salary: ' || v_min_salary);
dbms_output.put('Result? ');
IF v_emp_salary = v_min_salary THEN
dbms_output.put('Yes');
result := 1;
ELSE dbms_output.put('No');
result := 0;
END IF;
dbms_output.put_line(NULL);
dbms_output.put_line('++++++++++++++++++++++++');
return result;
END LOOP;
END;

Answer 3

The OP originally asked:
I am having a hard time placing [the cursor] inside a a function, how can I do this?
and
OPEN c_emp_salary('Shipping Clerk'); --I WANT THIS VALUE TO BE FROM A FUNCTION.
The code below solves the problem originally asked in the question; it is not intended to solve the assignment question that was edited in later as they are not one-and-the-same (that is left as an exercise to the OP).
Oracle Setup:
CREATE TABLE employees (
employee_id NUMBER,
first_name VARCHAR2(50),
salary NUMBER(10,2),
job_id NUMBER
);
CREATE TABLE jobs (
job_id NUMBER,
job_title VARCHAR2(50),
min_salary NUMBER(10,2)
);
INSERT INTO employees VALUES ( 1, 'Alice', 300, 1 );
INSERT INTO jobs VALUES ( 1, 'Shipping Clerk', 200 );
PL/SQL Block:
DECLARE
v_emp_id employees.employee_id%TYPE;
v_emp_first_name employees.first_name%TYPE;
v_emp_salary employees.salary%TYPE;
v_min_salary jobs.min_salary%TYPE;
c_emp_cursor SYS_REFCURSOR;
FUNCTION get_cursor(
v_job_title IN JOBS.JOB_TITLE%TYPE
) RETURN SYS_REFCURSOR
IS
c_emp_salary SYS_REFCURSOR;
BEGIN
OPEN c_emp_salary FOR
SELECT employee_id,
first_name,
salary,
min_salary
FROM employees e
JOIN jobs j
ON ( e.job_id = j.job_id
AND j.job_title = v_job_title );
RETURN c_emp_salary;
END;
BEGIN
c_emp_cursor := get_cursor('Shipping Clerk');
LOOP
FETCH c_emp_cursor INTO v_emp_id, v_emp_first_name, v_emp_salary, v_min_salary;
EXIT WHEN c_emp_cursor%NOTFOUND;
dbms_output.put_line('Employee ID: ' || v_emp_id);
dbms_output.put_line('Employee First Name: ' || v_emp_first_name);
dbms_output.put_line('Employee Salary: ' || v_emp_salary);
dbms_output.put_line('Job Min Salary: ' || v_min_salary);
dbms_output.put('Result? ');
IF v_emp_salary = v_min_salary THEN dbms_output.put('Yes');
ELSE dbms_output.put('No');
END IF;
dbms_output.put_line(NULL);
dbms_output.put_line('++++++++++++++++++++++++');
END LOOP;
END;
/
Output:
Employee ID: 1
Employee First Name: Alice
Employee Salary: 300
Job Min Salary: 200
Result? No
++++++++++++++++++++++++
db<>fiddle here