SQL Quiz-3

Which of the following is a DDL command?

• UPDATE
• CREATE
• DELETE
• SELECT

Which command is used to remove all rows from a table but keep its structure?

• TRUNCATE TABLE
• CLEAR TABLE
• DROP TABLE
• DELETE FROM

DQL commands are primarily used to:

• retrieve data from a database
• create new tables in a database
• update data in a database
• delete data from a database

Identify the DML commands from the list below. (Multiple correct)

• UPDATE

• CREATE

• DELETE

• ALTER

What will the following query do?

ALTER TABLE employees ADD COLUMN department_id INT;

• Add a new row to employees table

• Add a new column to students table

• Add a new column to employees table

• Create a new table

Which query correctly retrieves unique department names from the departments table?

• SELECT department_name FROM departments;

• SELECT UNIQUE department_name FROM departments;

• SELECT DISTINCT department_name FROM departments;

• SELECT department_name DISTINCT FROM departments;

Which of the following functions is NOT an aggregation function?

• SUM()

• COUNT()

• MAX()

• ROUND()

Which clause is used to filter aggregated results in SQL?

• ORDER BY
• HAVING
• GROUP BY
• WHERE

Which query will return the total salary for each department, only for departments having total salary > 50000?

• SELECT department_id, SUM(salary)

  FROM employees

  WHERE SUM(salary) > 50000

  GROUP BY department_id;

• SELECT department_id, SUM(salary)

  FROM employees

  GROUP BY department_id

  HAVING SUM(salary) > 50000;

• SELECT department_id, salary

  FROM employees

  HAVING SUM(salary) > 50000;

• SELECT department_id, SUM(salary)

  FROM employees

  WHERE salary > 50000

  GROUP BY department_id;

Which query correctly counts the number of distinct job titles in employees table?

• SELECT COUNT(job_title) FROM employees;

• SELECT DISTINCT COUNT(job_title) FROM employees;

• SELECT COUNT(DISTINCT job_title) FROM employees;

• SELECT job_title COUNT(DISTINCT) FROM employees;