The document contains 3 SQL queries: 1. Finds the top 10 senior engineers with average salary over $110,000 ordered by average salary descending. 2. Finds the top 10 employees who earned over $200,000 between 2000-2002 ordered by total wages descending. 3. Uses a subquery to display the bottom 10 average salaries of employees not in the 'Staff' category.

1. 1. Return the names, IDS, and average salary of the top 10 employees who are Senior Engineers
whose average salary is at least $110,000 in descending order.
2. Find the top ten employees (names, IDs and total wages) who earned equal to or more than
$200000 between 01/01/2000 and 01/01/2002. Order them in decreasing order. Assume salaries
change every 12 months. For simplicity, ignore salaries that started or ended outside of the date
range.
3. Use a subquery to display the employee number and bottom 10 average salaries of the
employees who are not 'Staff'.
It is for MySQL, so the statements are slightly fifferent than SQL etc.
Solution
CREATE TABLE employees (
emp_no INT(11) NOT NULL,
birth_date DATE NOT NULL,
first_name VARCHAR(14) NOT NULL,
last_name VARCHAR(16) NOT NULL,
gender ENUM(‘M’,’F’) NOT NULL,
hire_date DATE NOT NULL,
PRIMARY KEY(emp_no) );
CREATE TABLE departments (
dept_no CHAR(4) NOT NULL,
dept_name VARCHAR(40) NOT NULL,

2. PRIMARY KEY(dept_no) );
UNIQUE KEY(dept_name) );
CREATE TABLE dept_emp (
emp_no INT(11) NOT NULL,
dept_no CHAR(4) NOT NULL,
from_date DATE NOT NULL,
to_date DATE NOT NULL,
PRIMARY KEY(emp_no) ,
FOREIGN KEY(emp_no) REFERENCES employees(emp_no),
FOREIGN KEY(dept_no) REFERENCES departments(dept_no),
PRIMARY KEY(dept_no) );
CREATE TABLE dept_manager (
emp_no INT(11) NOT NULL,
dept_no CHAR(4) NOT NULL,
from_date DATE NOT NULL,
to_date DATE NOT NULL,
PRIMARY KEY(emp_no) ,
FOREIGN KEY(emp_no) REFERENCES employees(emp_no),
FOREIGN KEY(dept_no) REFERENCES departments(dept_no),
PRIMARY KEY(dept_no) );
CREATE TABLE salaries (
emp_no INT(11) NOT NULL,
salary INT(11) NOT NULL,

3. from_date DATE NOT NULL,
to_date DATE NOT NULL,
PRIMARY KEY(emp_no) );
FOREIGN KEY(emp_no) REFERENCES employees(emp_no)
);
CREATE TABLE titles (
emp_no INT(11) NOT NULL,
title VARCHAR(50) NOT NULL,
from_date DATE NOT NULL,
to_date DATE NOT NULL,
PRIMARY KEY(emp_no) );
FOREIGN KEY(emp_no) REFERENCES employees(emp_no)
);
WHERE avg(salary) > = $110000ORDER BY avg(salary)desc limit 0,10
2. SELECT CONCAT(last_name,first_name) AS emp_name,emp_no,salary  FROM
employees
WHERE salary>=$200000 BETWEEN 01-01-2000 AND 01-01-2001 AND|OR
salary>=$200000 BETWEEN 01-01-2001 AND 01-01-2002 ORDER BY salary desc limit 0,10
3. SELECT emp_no FROM employees
WHERE salary>(SELECT avg(salary)
FROM employees
WHERE NOT EXISTS (SELECT name FROM employees)
)
ORDER BY emp_no ASC