Translate the following question to SQL: What are the total number of domestic passengers at all London airports?

Schema: CREATE TABLE pilot (
    Pilot_Id int(11) NOT NULL  PRIMARY KEY,
    Name varchar(50) NOT NULL,
    Age int(11) NOT NULL,
    UNIQUE (Pilot_Id)
);

CREATE TABLE aircraft (
    Aircraft_ID int(11) NOT NULL  PRIMARY KEY,
    Aircraft varchar(50) NOT NULL,
    Description varchar(50) NOT NULL,
    Max_Gross_Weight varchar(50) NOT NULL,
    Total_disk_area varchar(50) NOT NULL,
    Max_disk_Loading varchar(50) NOT NULL,
    UNIQUE (Aircraft_ID)
);

CREATE TABLE match (
    Round REAL   PRIMARY KEY,
    Location TEXT,
    Country TEXT,
    Date TEXT,
    Fastest_Qualifying TEXT,
    Winning_Pilot TEXT,
    Winning_Aircraft TEXT,
    UNIQUE (Round),
    FOREIGN KEY (Winning_Pilot) REFERENCES pilot(Pilot_Id),
    FOREIGN KEY (Winning_Aircraft) REFERENCES aircraft(Aircraft_ID)
);

CREATE TABLE airport (
    Airport_ID INT   PRIMARY KEY,
    Airport_Name TEXT,
    Total_Passengers REAL,
    %_Change_2007 TEXT,
    International_Passengers REAL,
    Domestic_Passengers REAL,
    Transit_Passengers REAL,
    Aircraft_Movements REAL,
    Freight_Metric_Tonnes REAL,
    UNIQUE (Airport_ID)
);

CREATE TABLE airport_aircraft (
    ID INT,
    Airport_ID INT   PRIMARY KEY,
    Aircraft_ID INT   PRIMARY KEY,
    PRIMARY KEY (Airport_ID, Aircraft_ID),
    UNIQUE (Airport_ID, Aircraft_ID),
    FOREIGN KEY (Aircraft_ID) REFERENCES aircraft(Aircraft_ID),
    FOREIGN KEY (Airport_ID) REFERENCES airport(Airport_ID)
);
user
SELECT sum(Domestic_Passengers) FROM airport WHERE Airport_Name LIKE "%London%"
assistant