ORDER BY with NULLS FIRST and NULLS LAST in PostgreSQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to order the results by the column score in ascending order with NULL values appearing first.

PostgreSQL

SELECT * FROM players ORDER BY score [1];

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

ANULLS FIRST

BASC

CNULLS LAST

DDESC

Attempts:

3 left

💡 Hint

Common Mistakes

Using only ASC without NULLS FIRST will put NULLs last by default.

Using DESC instead of NULLS FIRST changes the order direction.

Using ORDER BY score NULLS FIRST sorts the scores in ascending order by default and places NULL values at the beginning.

2fill in blank

medium

Complete the code to order the results by the column date_joined in descending order with NULL values appearing last.

PostgreSQL

SELECT * FROM members ORDER BY date_joined [1];

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

ANULLS FIRST

BNULLS LAST

CDESC NULLS LAST

DDESC

Attempts:

3 left

💡 Hint

Common Mistakes

Using only DESC puts NULLs first by default.

Using NULLS FIRST will put NULLs at the beginning, which is not desired here.

Using ORDER BY date_joined DESC NULLS LAST sorts dates from newest to oldest and places NULL values at the end.

3fill in blank

hard

Fix the error in the code to order by price ascending with NULL values last.

PostgreSQL

SELECT * FROM products ORDER BY price [1];

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

AASC NULLS FIRST

BNULLS LAST

CDESC NULLS LAST

DASC NULLS LAST

Attempts:

3 left

💡 Hint

Common Mistakes

Using only NULLS LAST without ASC or DESC causes syntax error.

Using DESC NULLS LAST changes the order direction.

The correct syntax to order ascending with NULLs last is ASC NULLS LAST.

4fill in blank

hard

Fill both blanks to order by rating descending with NULL values first.

PostgreSQL

SELECT * FROM reviews ORDER BY rating [1] [2];

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

ADESC

BNULLS FIRST

CASC

DNULLS LAST

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the order direction and NULLS clause.

Using NULLS LAST when NULLS FIRST is required.

Ordering by rating DESC NULLS FIRST sorts ratings from highest to lowest and puts NULLs at the beginning.

5fill in blank

hard

Fill all three blanks to order by score ascending with NULL values last, then by name descending with NULL values first.

PostgreSQL

SELECT * FROM leaderboard ORDER BY score [1] [2], name [3];

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

AASC

BNULLS LAST

CDESC NULLS FIRST

DDESC

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to specify NULLS position for one or both columns.

Mixing up ASC and DESC directions.

The query orders first by score ASC NULLS LAST (lowest scores first, NULLs last), then by name DESC NULLS FIRST (names descending, NULLs first).