Translate the following question to SQL: What is the number of employees?

Schema: CREATE TABLE flight (
    flno number(4,0)   PRIMARY KEY,
    origin varchar2(20),
    destination varchar2(20),
    distance number(6,0),
    departure_date date,
    arrival_date date,
    price number(7,2),
    aid number(9,0),
    UNIQUE (flno),
    FOREIGN KEY (aid) REFERENCES aircraft(aid)
);

CREATE TABLE aircraft (
    aid number(9,0)   PRIMARY KEY,
    name varchar2(30),
    distance number(6,0),
    UNIQUE (aid)
);

CREATE TABLE employee (
    eid number(9,0)   PRIMARY KEY,
    name varchar2(30),
    salary number(10,2),
    UNIQUE (eid)
);

CREATE TABLE certificate (
    eid number(9,0)   PRIMARY KEY,
    aid number(9,0)   PRIMARY KEY,
    PRIMARY KEY (eid, aid),
    UNIQUE (eid, aid),
    FOREIGN KEY (aid) REFERENCES aircraft(aid),
    FOREIGN KEY (eid) REFERENCES employee(eid)
);
user
SELECT count(*) FROM Employee
assistant