Why DELETE needs caution in SQL - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to delete all rows from the table named 'employees'.

SQL

DELETE FROM [1];

Drag options to blanks, or click blank then click option'

Aemp

Bemployee

Cemployees

Dstaff

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong table name causes an error or deletes nothing.

Misspelling the table name.

The correct table name is 'employees'. Using the exact table name is important to delete the intended data.

2fill in blank

medium

Complete the code to delete only employees with the job title 'Intern'.

SQL

DELETE FROM employees WHERE job_title = [1];

Drag options to blanks, or click blank then click option'

A'Intern'

B'Manager'

C'Engineer'

D'Clerk'

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around text values.

Deleting the wrong job title.

We want to delete only rows where the job_title is 'Intern'. The value must be in quotes because it is text.

3fill in blank

hard

Fix the error in the DELETE statement to remove employees hired before 2020.

SQL

DELETE FROM employees WHERE hire_date [1] '2020-01-01';

Drag options to blanks, or click blank then click option'

A>

B<

C=

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using greater than deletes employees hired after 2020.

Using equal deletes only those hired exactly on 2020-01-01.

To delete employees hired before 2020, use the less than operator (<) comparing hire_date to '2020-01-01'.

4fill in blank

hard

Fill both blanks to delete employees from the 'sales' department hired after 2018.

SQL

DELETE FROM employees WHERE department = [1] AND hire_date [2] '2018-12-31';

Drag options to blanks, or click blank then click option'

A'sales'

B'marketing'

C>

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong department name.

Using less than or equal operator deletes wrong rows.

We delete employees in the 'sales' department (text in quotes) hired after 2018 (use > operator).

5fill in blank

hard

Fill all three blanks to delete employees with salary less than 30000 and job title 'Assistant'.

SQL

DELETE FROM [1] WHERE salary [2] [3] AND job_title = 'Assistant';

Drag options to blanks, or click blank then click option'

Aemployees

B<

C30000

Dstaff

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong table name.

Using quotes around salary number.

Using wrong comparison operator.

We delete from 'employees' table where salary is less than 30000 and job title is 'Assistant'.