NTILE for distribution in PostgreSQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to divide rows into 4 groups using NTILE.

PostgreSQL

SELECT name, salary, NTILE([1]) OVER (ORDER BY salary) AS quartile FROM employees;

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A4

B3

C5

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using 3 or 5 instead of 4 for quartiles.

Forgetting to order rows inside OVER clause.

The NTILE function divides rows into the specified number of groups. Here, 4 groups (quartiles) are needed.

2fill in blank

medium

Complete the code to assign 3 groups to rows ordered by score.

PostgreSQL

SELECT player, score, NTILE([1]) OVER (ORDER BY score DESC) AS group_num FROM leaderboard;

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A3

B2

C4

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong number of groups.

Not ordering scores descending to get top scores first.

NTILE(3) divides the rows into 3 groups ordered by score descending.

3fill in blank

hard

Complete the code to divide rows into 5 groups.

PostgreSQL

SELECT id, value, NTILE([1]) OVER (ORDER BY value) AS group_id FROM data;

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A4

B6

C3

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Missing ORDER BY inside OVER clause.

Using wrong number of groups.

The NTILE function needs the number of groups as argument. Here, 5 groups are required.

4fill in blank

hard

Fill both blanks to divide employees into 3 groups ordered by age.

PostgreSQL

SELECT name, age, NTILE([1]) OVER (ORDER BY [2]) AS age_group FROM employees;

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A3

Bage

Csalary

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong column in ORDER BY.

Using wrong number of groups.

NTILE(3) divides into 3 groups. Ordering by age sorts rows by age for grouping.

5fill in blank

hard

Fill all three blanks to create quartiles of sales and show group and sales.

PostgreSQL

SELECT salesperson, sales, NTILE([1]) OVER (ORDER BY [2] [3]) AS sales_quartile FROM sales_data;

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A4

Bsales

CDESC

DASC

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong number of groups.

Ordering by wrong column or wrong direction.

NTILE(4) creates 4 groups (quartiles). Ordering by sales ascending groups from lowest to highest sales.