mySQL Basics- Haroon Ahmad

queries.sql

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+/* Adding Employees to the Table  */
+
+INSERT INTO employees (emp_no, birth_date, first_name, last_name, gender, hire_date) values (1, '1995-01-21', 'Haroon', 'Ahmad','M',  '2015-09-21'), (2, '1979-09-09', 'Franklin', 'Collins', 'M', '2012-12-29'), (3, '1989-11-29', 'Arsalan', 'Ahmed', 'M', '2021-09-21');    
+
+INSERT INTO employees (emp_no, birth_date, first_name, last_name, gender, hire_date) values (4, '1975-01-21', 'Tommy', 'Vercetti','M',  '2005-09-21'), (5, '1969-09-09', 'Ken', 'Markowski', 'M', '2013-12-19'), (6, '1967-06-29', 'Tervor', 'Philips', 'M', '2001-09-21'), (7, '1975-02-12', 'Michael', 'Da Santo', 'M', '2016-08-30'), (8, '1979-08-07', 'Lance', 'Vance', 'M', '2003-01-13'), (9, '1955-12-12', 'Uncle', 'Billy', 'M', '1996-10-21'), (10, '1990-02-14', 'Sonia', 'Sonny', 'F', '2018-09-30'), (11, '2000-02-29', 'Lester', 'Crest', 'M', '2019-01-01'), (12, '1990-08-20', 'Leonardo', 'Da Vinci', 'M', '2015-05-06');
+
+INSERT INTO employees (emp_no, birth_date, first_name, last_name, gender, hire_date) values (13, '1980-02-20', 'Ezio', 'Auditore', 'M', '2002-05-30'), (14, '2000-09-01', 'Jimmy', 'Da Santa', 'M', '2021-09-01'), (15, '1980-01-20', 'Lamar', 'Davis', 'M', '2014-05-06');
+
+
+/*Adding Salaries corresponding to employees */
+
+INSERT INTO salaries (emp_no, salary, from_date, to_date) values (1, 20000, '2015-09-21', '2016-09-21'), (1, 40000, '2016-09-21', '2019-09-21'), (1, 79000, '2019-09-21', now()), (2, 20000, '2012-12-29', '2016-12-21'), (2, 50000, '2016-12-21', now()), (3, 20000, '2021-09-21', now()), (4, 5000, '2021-09-21', now());
+
+INSERT INTO salaries (emp_no, salary, from_date, to_date) values (5, 20000, '2013-12-19', now()), (6, 39000, '2001-09-21', now()), (7, 45000, '2016-08-30', now()), (8, 69000, '2003-01-13', now()), (9, 99999, '1996-10-21', now()), (10, 35000, ' 2018-09-30', now()),(11, 20000, '2019-01-01', now()),(12, 50000, '2015-05-06', now()),(13, 80000, '2002-05-30', now()), (14, 1000, '2021-09-01', now()), (15, 45000, '2014-05-06', now());
+
+/* Create Departments */
+
+INSERT INTO departments (dept_no, dept_name) values ('1a', 'Planning and Relations'), ( '1b', 'On Field and Execution'), ('2a', 'Pilots'), ('2b', 'Legal Department'), ('2c', 'Banking'), ('3', 'Laundering');
+
+/* Adding Employees to Departments */
+
+INSERT INTO dept_emp (emp_no, dept_no, from_date, to_date) values (1, '1a', '2015-09-21', now()), (1, '1b', '2018-12-21', now()), (2, '2a', '2012-12-29', now()), (3, '2c', '2021-09-21', now()),(14, '2c', '2021-09-01', now()), (4, '1b', '2005-09-21', now()), (5, '2b', '2013-12-19', now() ), (5, '3', '2013-12-19', now());
+
+INSERT INTO dept_emp (emp_no, dept_no, from_date, to_date) values (6, '1b', '2001-09-21', now()), (7, '1b', '2016-08-30', now()), (8, '1b', '2003-01-13', now()), (9, '3', '1996-10-21', now()), (10, '1b', '2018-09-30', now()), (11, '1b', '2019-01-01', now()), (12, '1b', '2015-05-06', now()), (13, '1b', '2002-05-30', now()), (14, '1b', '2021-09-01', now() ), (15, '1b', '2014-05-06', now() );
+
+/* Adding Employees as Department Managers */
+
+INSERT INTO  dept_manager values (1, '1a', '2015-09-21', now()), (11, '3', '2019-01-01', now()), (4, '1b', '2005-09-21', now()), (3, '2c', '2021-09-21', now() ), (5, '2b', '2013-12-19', now());
+
+/* Adding 2 more Employees with same names */
+
+INSERT INTO employees values (16, '1985-01-03', 'Tommy', 'Bolt', 'M', now()), (17, '1992-05-09', 'Tommy', 'Burrito', 'M', now());
+
+/* Changing Name of an Employee based on name, surname and DOB */
+
+UPDATE employees SET first_name = "Tom" WHERE last_name = "Burrito";
+
+UPDATE employees SET last_name = "Clinton" WHERE first_name = "Franklin";
+
+UPDATE employees SET hire_date = "2002-12-29" WHERE first_name = "Franklin";
+
+/* Select all employees with a salary greater than 20,000 */ 
+
+SELECT * 
+FROM employees 
+INNER JOIN salaries
+ON salaries.emp_no = employees.emp_no AND salaries.salary > 20000;
+
+/* Select all employees with a salary below 10,000 */
+
+
+SELECT * 
+FROM employees 
+INNER JOIN salaries
+ON salaries.emp_no = employees.emp_no AND salaries.salary < 10000;
+
+/* Select all employees who have a salary between 14.00 and 50,000 */
+
+SELECT * 
+FROM employees 
+INNER JOIN salaries
+ON salaries.emp_no = employees.emp_no AND salaries.salary > 14000 AND salaries.salary < 50000;
+
+/* Select the total number of employees */
+
+SELECT * FROM employees; /*Gives the Full data of all employees */
+
+SELECT COUNT(*) FROM employees; /* Number of Employees */
+
+
+/* Select Employees who have worked in more than one department */
+
+
+select * from dept_emp;
+SELECT
+    emp_no,
+    COUNT(emp_no)
+FROM dept_emp
+GROUP BY (emp_no)
+HAVING COUNT(emp_no) > 1;
+
+/* Select Employees who have worked as Managers */
+
+SELECT first_name, last_name
+FROM employees
+INNER JOIN dept_manager
+ON dept_manager.emp_no = employees.emp_no;
+
+/* Select Employees with first_name in uppercase */
+
+SELECT UCASE(first_name) FROM employees;
+
+/* Select the name, surname and name of the current department of each employee */
+
+SELECT employees.first_name, employees.last_name, dept_emp.dept_no
+FROM employees
+INNER JOIN dept_emp ON employees.emp_no = dept_emp.emp_no
+ORDER BY dept_emp.dept_no;
+
+/* Select the name, surname and number of times the employee has worked as a manager */
+
+SELECT
+ COUNT(dept_manager.emp_no),
+ employees.first_name, 
+ employees.last_name
+FROM dept_manager
+INNER JOIN employees
+ON dept_manager.emp_no = employees.emp_no
+
+GROUP BY dept_manager.emp_no 
+HAVING COUNT(dept_manager.emp_no) >0;
+
+/*Delete all employees with a salary greater than 20,000 */
+
+DELETE employees , salaries
+FROM employees
+INNER JOIN salaries
+ON salaries.emp_no = employees.emp_no AND salaries.salary > 20000;
+
+/* Remove the department that has more employees */
+