ALTER TABLE loan_rate_tables
    ADD COLUMN product_type VARCHAR(100) NULL AFTER bank_id,
    ADD COLUMN sub_product_id INT UNSIGNED NULL AFTER product_type,
    ADD CONSTRAINT fk_loan_rate_tables_sub_product FOREIGN KEY (sub_product_id) REFERENCES loan_sub_products (id) ON DELETE SET NULL,
    ADD INDEX idx_loan_rate_tables_product (product_type),
    ADD INDEX idx_loan_rate_tables_sub_product (sub_product_id);