Oracle 21c

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ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
CREATE TABLE bank_account (account_id, customer_id, currency_id, balance) AS
SELECT 1, 1, 1, 100000 FROM DUAL UNION ALL
SELECT 2, 1, 2, 100000 FROM DUAL UNION ALL
SELECT 3, 1, 3, 200000 FROM DUAL;
3 rows affected

CREATE TABLE currency (currency_id, course_to_lev) AS
SELECT 1, 0.5 FROM DUAL UNION ALL
SELECT 2, 0.25 FROM DUAL UNION ALL
SELECT 3, 0.125 FROM DUAL;
3 rows affected

CREATE TABLE vip_customer (customer_id) AS
SELECT customer_id FROM bank_account WHERE 1 = 0;
CREATE TYPE id_list
  AS TABLE OF NUMBER(10,0) -- Match data type of BANK_ACCOUNT.CUSTOMER_ID
CREATE TRIGGER add_new_vip
FOR UPDATE OF BALANCE ON BANK_ACCOUNT
COMPOUND TRIGGER
  ids id_list := id_list();
AFTER EACH ROW
  IS
  BEGIN
    ids.EXTEND;
    ids(ids.COUNT) := :NEW.customer_id;
  END AFTER EACH ROW;  
AFTER STATEMENT
  IS
  BEGIN
    MERGE INTO vip_customer dst
    USING (
      SELECT a.customer_id
      FROM   bank_account a
             INNER JOIN currency c
             ON a.currency_id = c.currency_id
      WHERE  a.customer_id IN (SELECT COLUMN_VALUE FROM TABLE(ids))
      GROUP BY a.customer_id
      HAVING SUM(a.balance *c.course_to_lev) > 100000
    ) src
    ON (dst.customer_id = src.customer_id)
    WHEN NOT MATCHED THEN
      INSERT (CUSTOMER_ID) VALUES (src.customer_id);
  END AFTER STATEMENT;
END;
/
    SELECT a.customer_id,
           SUM(a.balance *c.course_to_lev)
    FROM   bank_account a
           INNER JOIN currency c
           ON a.currency_id = c.currency_id
    WHERE  a.customer_id = 1
    GROUP BY a.customer_id


CUSTOMER_ID
SUM(A.BALANCE*C.COURSE_TO_LEV)


1
100000


SELECT * FROM vip_customer;
UPDATE bank_account
SET balance = 200001
WHERE account_id = 3
1 rows affected

    SELECT a.customer_id,
           SUM(a.balance *c.course_to_lev)
    FROM   bank_account a
           INNER JOIN currency c
           ON a.currency_id = c.currency_id
    WHERE  a.customer_id = 1
    GROUP BY a.customer_id


CUSTOMER_ID
SUM(A.BALANCE*C.COURSE_TO_LEV)


1
100000.125


SELECT * FROM vip_customer;


CUSTOMER_ID


1