Nested CASE expressions in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return 'High' when score is above 80 using a CASE expression.

SQL

SELECT CASE WHEN score [1] 80 THEN 'High' ELSE 'Low' END AS performance FROM results;

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

A=

B<

C<=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' will label scores below 80 as 'High'.

Using '=' will only label scores exactly 80 as 'High'.

The condition checks if the score is greater than 80 to label it as 'High'.

2fill in blank

medium

Complete the code to return 'Medium' when score is between 50 and 80 using nested CASE expressions.

SQL

SELECT CASE WHEN score > 80 THEN 'High' WHEN score [1] 50 THEN 'Medium' ELSE 'Low' END AS performance FROM results;

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

A<

B>=

C=

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' instead of '>=' will incorrectly classify scores below 50 as 'Medium'.

Using '=' only matches score exactly 50.

The condition checks if the score is greater than or equal to 50 to assign 'Medium' for scores between 50 and 80.

3fill in blank

hard

Fix the error in the nested CASE expression to correctly classify scores.

SQL

SELECT CASE WHEN score > 80 THEN 'High' WHEN score [1] 50 THEN 'Medium' ELSE 'Low' END AS performance FROM results;

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

A>=

B<=

C<

D=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' will incorrectly classify scores below 50 as 'Medium'.

Using '=' only matches score exactly 50.

The condition should check if score is greater than or equal to 50 to classify as 'Medium'.

4fill in blank

hard

Fill both blanks to classify scores into 'High', 'Medium', or 'Low' using nested CASE expressions.

SQL

SELECT CASE WHEN score [1] 80 THEN 'High' WHEN score [2] 50 THEN 'Medium' ELSE 'Low' END AS performance FROM results;

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

A>

B<=

C>=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the operators will misclassify scores.

Using '<=' in the first blank will cause wrong results.

The first condition checks if score is greater than 80 for 'High'. The second checks if score is greater than or equal to 50 for 'Medium'.

5fill in blank

hard

Fill all three blanks to create a nested CASE expression that classifies scores into 'Excellent', 'Good', 'Average', or 'Poor'.

SQL

SELECT CASE WHEN score [1] 90 THEN 'Excellent' WHEN score [2] 75 THEN 'Good' WHEN score [3] 50 THEN 'Average' ELSE 'Poor' END AS performance FROM results;

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

A>=

B<

C>

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' for the first two blanks will misclassify scores.

Using '<=' instead of '>=' for the last blank will misclassify low scores.

The first two blanks use '>' to check if score is above 90 and 75. The third uses '>=' to check greater than or equal to 50 for 'Average'.