Translate the following question to SQL: What is the phone number of the customer who has filed the most recent complaint?

Schema: CREATE TABLE Staff (
    staff_id INTEGER   PRIMARY KEY,
    gender VARCHAR(1),
    first_name VARCHAR(80),
    last_name VARCHAR(80),
    email_address VARCHAR(255),
    phone_number VARCHAR(80)
);

CREATE TABLE Customers (
    customer_id INTEGER   PRIMARY KEY,
    customer_type_code VARCHAR(20) NOT NULL,
    address_line_1 VARCHAR(80),
    address_line_2 VARCHAR(80),
    town_city VARCHAR(80),
    state VARCHAR(80),
    email_address VARCHAR(255),
    phone_number VARCHAR(80)
);

CREATE TABLE Products (
    product_id INTEGER   PRIMARY KEY,
    parent_product_id INTEGER,
    product_category_code VARCHAR(20) NOT NULL,
    date_product_first_available DATETIME,
    date_product_discontinued DATETIME,
    product_name VARCHAR(80),
    product_description VARCHAR(255),
    product_price DECIMAL(19,4)
);

CREATE TABLE Complaints (
    complaint_id INTEGER NOT NULL,
    product_id INTEGER NOT NULL,
    customer_id INTEGER NOT NULL,
    complaint_outcome_code VARCHAR(20) NOT NULL,
    complaint_status_code VARCHAR(20) NOT NULL,
    complaint_type_code VARCHAR(20) NOT NULL,
    date_complaint_raised DATETIME,
    date_complaint_closed DATETIME,
    staff_id INTEGER NOT NULL,
    FOREIGN KEY (customer_id) REFERENCES Customers(customer_id),
    FOREIGN KEY (product_id) REFERENCES Products(product_id),
    FOREIGN KEY (staff_id) REFERENCES Staff(staff_id)
);
user
SELECT t1.phone_number FROM customers AS t1 JOIN complaints AS t2 ON t1.customer_id  =  t2.customer_id ORDER BY t2.date_complaint_raised DESC LIMIT 1
assistant