Translate the following question to SQL: What are the total purchases for members rated at level 6?

Schema: CREATE TABLE member (
    Member_ID INT   PRIMARY KEY,
    Card_Number TEXT,
    Name TEXT,
    Hometown TEXT,
    Level INT,
    UNIQUE (Member_ID)
);

CREATE TABLE branch (
    Branch_ID INT   PRIMARY KEY,
    Name TEXT,
    Open_year TEXT,
    Address_road TEXT,
    City TEXT,
    membership_amount TEXT,
    UNIQUE (Branch_ID)
);

CREATE TABLE membership_register_branch (
    Member_ID INT   PRIMARY KEY,
    Branch_ID TEXT,
    Register_Year TEXT,
    UNIQUE (Member_ID),
    FOREIGN KEY (Branch_ID) REFERENCES branch(Branch_ID),
    FOREIGN KEY (Member_ID) REFERENCES member(Member_ID)
);

CREATE TABLE purchase (
    Member_ID INT   PRIMARY KEY,
    Branch_ID TEXT   PRIMARY KEY,
    Year TEXT   PRIMARY KEY,
    Total_pounds REAL,
    PRIMARY KEY (Member_ID, Branch_ID, Year),
    UNIQUE (Member_ID, Branch_ID, Year),
    FOREIGN KEY (Branch_ID) REFERENCES branch(Branch_ID),
    FOREIGN KEY (Member_ID) REFERENCES member(Member_ID)
);
user
SELECT count(*) FROM purchase AS T1 JOIN member AS T2 ON T1.member_id  =  T2.member_id WHERE T2.level  =  6
assistant