SELECT dept_name FROM instructor GROUP BY dept_name ORDER BY AVG(salary) DESC LIMIT 1
Which department has the highest average instructor salary?
CREATE TABLE instructor (
    id text,
    name text,
    dept_name text,
    salary number
)

CREATE TABLE section (
    course_id text,
    sec_id text,
    semester text,
    year number,
    building text,
    room_number text,
    time_slot_id text
)

CREATE TABLE classroom (
    building text,
    room_number text,
    capacity number
)

CREATE TABLE department (
    dept_name text,
    building text,
    budget number
)

CREATE TABLE time_slot (
    time_slot_id text,
    day text,
    start_hr number,
    start_min number,
    end_hr number,
    end_min number
)

CREATE TABLE course (
    course_id text,
    title text,
    dept_name text,
    credits number
)

CREATE TABLE teaches (
    id text,
    course_id text,
    sec_id text,
    semester text,
    year number
)

CREATE TABLE prereq (
    course_id text,
    prereq_id text
)

CREATE TABLE student (
    id text,
    name text,
    dept_name text,
    tot_cred number
)

CREATE TABLE takes (
    id text,
    course_id text,
    sec_id text,
    semester text,
    year number,
    grade text
)

CREATE TABLE advisor (
    s_id text,
    i_id text
)