PL SQL loop through list of ids - sql

Question

I have a list of names.
john, sam, peter, jack
I want to query the same sql with each of above as the filter. Each query will give me a unique employee id, which I want to use to delete some other records.
select emp_id from employee where emp_name like '%john%';
Let's say for the first query, I get the id as 1001. So the delete queries would be like following.
delete from account_details where emp_id = 1001;
delete from hr_details where emp_id = 1001;
delete from pay_role_details where emp_id = 1001;
I have to repeat this for a list of employees. Pseudocode would be like following.
var emp_list = ['john', 'jack', 'kate', 'peter', 'sam',...]
for each :employee_name in emp_list
select emp_id as :var_emp_id from employee where emp_name like '%:employee_name%';
delete from account_details where emp_id = :var_emp_id;
delete from hr_details where emp_id = :var_emp_id;
delete from pay_role_details where emp_id = :var_emp_id;
end loop
I want a PL-SQL query to do this. Please help. Thanks.
What I tried is something like the following.
set serveroutput on;
begin
loop x in ('john','jack', 'kate') loop as :name
select emp_id as var_emp_id from employee where emp_name like '%:name%';
// delete queries
end loop;
end;
P.S. Although accoring to the question, like query may result in multiple records, in actual scenario, it is guaranteed to be only one record. Why I use like is that in actual scenario, it is a list of reference numbers instead of names. The reference number has some other pre texts and post texts and my comma seperated list has only the numbers.

Answer 1

Perhaps the following will help:
BEGIN
FOR aName IN (SELECT 'john' AS EMP_NAME FROM DUAL
UNION ALL
SELECT 'sam' AS EMP_NAME FROM DUAL
UNION ALL
SELECT 'peter' AS EMP_NAME FROM DUAL
UNION ALL
SELECT 'jack' AS EMP_NAME FROM DUAL)
LOOP
FOR emp IN (SELECT * FROM EMPLOYEE WHERE EMP_NAME LIKE '%' || aName.EMP_NAME || '%')
LOOP
DELETE FROM ACCOUNT_DETAILS a WHERE a.EMP_ID = emp.EMP_ID;
DELETE FROM HR_DETAILS h WHERE h.EMP_ID = emp.EMP_ID;
DELETE FROM PAY_ROLE_DETAILS p WHERE p.EMP_ID = emp.EMP_ID;
DBMS_OUTPUT.PUT_LINE('Deleted data for employee with EMP_ID=' || emp.EMP_ID);
END LOOP; -- emp
END LOOP; -- aName
END;
Study this until you understand how and why it works.
Share and enjoy.

Answer 2

Do you really need a cursor to do so? Try to skip cursor if possible to avoid poor performance/memory usage on huge data.
delete from account_details inner join employee on account_details.emp_id = employee.emp_id where WHERE CONTAINS(employee.emp_name, '"John" OR "Sam" OR "Max"', 1) >0;
delete from hr_details inner join employee on hr_details.emp_id = employee.emp_id where WHERE CONTAINS(employee.emp_name, '"John" OR "Sam" OR "Max"', 1) >0;
delete from pay_role_details inner join employee on pay_role_details.emp_id = employee.emp_id where WHERE CONTAINS(employee.emp_name, '"John" OR "Sam" OR "Max"', 1) >0;

Answer 3

Use a PL/SQL cursor to select all the IDs you want to delete and then just loop it and issue the DELETE statements with every pass.
In-depth info on cursors can be found here: http://www.oracle.com/technetwork/issue-archive/2013/13-mar/o23plsql-1906474.html
For dynamic SQL see here: http://docs.oracle.com/cd/E11882_01/appdev.112/e25519/dynamic.htm#LNPLS627
Code example:
PROCEDURE delete_stuff
IS
id AS NUMBER;
CURSOR your_cursor IS
SELECT emp_id FROM employee WHERE CONTAINS(employee.emp_name, '"John" OR "Sam" OR "Max"', 1) > 0;
OPEN your_cursor;
LOOP
FETCH your_cursor INTO id;
EXIT WHEN your_cursor%NOTFOUND;
EXECUTE IMMEDIATE 'DELETE FROM account_details WHERE emp_id = :id' USING id;
EXECUTE IMMEDIATE 'DELETE FROM hr_details WHERE emp_id = :id' USING id;
EXECUTE IMMEDIATE 'DELETE FROM pay_role_details WHERE emp_id = :id' USING id;
CLOSE your_cursor;
END LOOP;
EXCEPTION
WHEN OTHERS THEN NULL;
END delete_stuff;