Q8

Author: bnarath

Images/Q8_sample_output.png

@@ -0,0 +1,104 @@
+/* DATA ANALYSIS */
+
+SET datestyle to MDY, SQL;
+select now()::date;
+
+/* 
+List the following details of each employee: 
+employee number, last name, first name, sex, and salary.
+*/
+
+DROP VIEW IF EXISTS employee_details_and_salary;
+CREATE VIEW employee_details_and_salary AS
+SELECT emp.emp_no, emp.last_name, emp.first_name, emp.sex, sal.salary
+FROM employees AS emp
+LEFT JOIN salaries AS sal
+ON emp.emp_no = sal.emp_no;
+
+SELECT COUNT(*) FROM employee_details_and_salary;
+SELECT * FROM employee_details_and_salary LIMIT 10;
+
+/* List first name, last name, and hire date 
+for employees who were hired in 1986. */
+
+CREATE VIEW employees_hired_in_1986 AS  
+SELECT emp.first_name, emp.last_name, emp.hire_date
+FROM employees as emp
+WHERE EXTRACT(YEAR FROM emp.hire_date) = 1986;
+
+SELECT COUNT(*) FROM employees_hired_in_1986;
+SELECT * FROM employees_hired_in_1986 LIMIT 10;
+
+/* List the manager of each department with the following 
+information: department number, department name, 
+the manager's employee number, last name, first name.*/
+
+CREATE VIEW dept_manager_details AS 
+SELECT dep_mngr.dept_no, depts.dept_name, dep_mngr.emp_no, emp.last_name, emp.first_name 
+FROM dept_manager AS dep_mngr
+LEFT JOIN departments AS depts ON dep_mngr.dept_no = depts.dept_no
+LEFT JOIN employees AS emp ON dep_mngr.emp_no = emp.emp_no;
+
+SELECT COUNT(*) FROM dept_manager_details;
+SELECT * FROM dept_manager_details LIMIT 10;
+
+/* List the department of each employee with the following information:
+employee number, last name, first name, and department name.
+*/
+CREATE VIEW employee_dept_details AS
+SELECT emp.emp_no, emp.last_name, emp.first_name, dept.dept_name
+FROM employees as emp
+LEFT JOIN dept_emp ON emp.emp_no = dept_emp.emp_no
+LEFT JOIN departments AS dept ON dept_emp.dept_no = dept.dept_no;
+
+SELECT COUNT(*) FROM employee_dept_details;
+SELECT * FROM employee_dept_details LIMIT 10;
+
+
+/*
+List first name, last name, and sex for employees 
+whose first name is "Hercules" and last names begin with "B."
+*/
+
+SELECT emp.first_name, emp.last_name, emp.sex
+FROM employees as emp
+WHERE LOWER(emp.first_name) = 'hercules'
+AND emp.last_name LIKE 'B%';
+
+/*List all employees in the Sales department, 
+including their employee number, last name, first name, and department name.
+*/
+
+SELECT emp.emp_no, emp.last_name, emp.first_name, dept.dept_name
+FROM employees as emp
+LEFT JOIN dept_emp ON emp.emp_no = dept_emp.emp_no
+LEFT JOIN departments AS dept ON dept_emp.dept_no = dept.dept_no
+WHERE dept.dept_name = 'Sales';
+
+SELECT * FROM employee_dept_details
+WHERE dept_name = 'Sales';
+
+/*List all employees in the Sales and Development departments,
+including their employee number, last name, first name, and department name.
+*/
+
+SELECT emp.emp_no, emp.last_name, emp.first_name, dept.dept_name
+FROM employees as emp
+LEFT JOIN dept_emp ON emp.emp_no = dept_emp.emp_no
+LEFT JOIN departments AS dept ON dept_emp.dept_no = dept.dept_no
+WHERE dept.dept_name = 'Sales' OR dept.dept_name = 'Development';
+
+SELECT * FROM employee_dept_details
+WHERE dept_name = 'Sales' OR dept_name = 'Development';
+
+/*In descending order, list the frequency count of 
+employee last names, i.e., 
+how many employees share each last name.*/
+
+SELECT last_name, COUNT(*) AS freqency_count
+FROM employees
+GROUP BY last_name
+ORDER BY freqency_count DESC;
+
+
+

Output/Analysis.sql

@@ -18,5 +18,4 @@ select pg_sleep(1);
 COPY dept_emp FROM '/tmp/dept_emp.csv' DELIMITER ',' CSV HEADER;
 select pg_sleep(1);
 COPY dept_manager FROM '/tmp/dept_manager.csv' DELIMITER ',' CSV HEADER;
-select pg_sleep(1);
-
+select pg_sleep(1);