ROW_NUMBER function in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assign a unique row number to each employee ordered by salary.

SQL

SELECT employee_id, salary, ROW_NUMBER() OVER (ORDER BY [1]) AS row_num FROM employees;

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

Aname

Bemployee_id

Cdepartment

Dsalary

Attempts:

3 left

💡 Hint

Common Mistakes

Using a column that does not exist in the table.

Forgetting to use ORDER BY inside the OVER clause.

The ROW_NUMBER() function assigns a unique number to each row based on the order of the salary column.

2fill in blank

medium

Complete the code to reset the row number for each department.

SQL

SELECT employee_id, department, ROW_NUMBER() OVER (PARTITION BY [1] ORDER BY salary) AS dept_rank FROM employees;

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

Aemployee_id

Bname

Cdepartment

Dsalary

Attempts:

3 left

💡 Hint

Common Mistakes

Using ORDER BY column inside PARTITION BY.

Omitting PARTITION BY when grouping is needed.

The PARTITION BY clause groups rows by department, so row numbers restart for each department.

3fill in blank

hard

Fix the error in the code to correctly assign row numbers partitioned by department and ordered by hire_date.

SQL

SELECT employee_id, department, ROW_NUMBER() OVER (PARTITION BY [1] ORDER BY [2]) AS rn FROM employees;

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

Ahire_date

Bemployee_id

Cdepartment

Dsalary

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping PARTITION BY and ORDER BY columns.

Using a non-existent column in either clause.

The PARTITION BY should be department to reset numbering per department, and ORDER BY should be hire_date to order employees by their hire date.

4fill in blank

hard

Fill both blanks to assign row numbers partitioned by department and ordered by salary descending.

SQL

SELECT employee_id, department, salary, ROW_NUMBER() OVER (PARTITION BY [1] ORDER BY salary [2]) AS rank FROM employees;

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

Adepartment

Bemployee_id

CDESC

DASC

Attempts:

3 left

💡 Hint

Common Mistakes

Using ASC instead of DESC for descending order.

Partitioning by the wrong column.

Partitioning by department groups employees, and ordering by salary DESC ranks highest salary first.

5fill in blank

hard

Fill all three blanks to select employee name, assign row numbers partitioned by department, ordered by hire_date ascending.

SQL

SELECT [1], ROW_NUMBER() OVER (PARTITION BY [2] ORDER BY [3]) AS row_num FROM employees;

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

Aemployee_name

Bdepartment

Chire_date

Dsalary

Attempts:

3 left

💡 Hint

Common Mistakes

Using salary instead of hire_date for ordering.

Selecting wrong column for employee name.

Select employee_name, partition by department to group employees, and order by hire_date ascending to number employees by hire date.