JSONB existence (?) operator in PostgreSQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the JSONB column 'data' contains the key 'name'.

PostgreSQL

SELECT * FROM users WHERE data [1] 'name';

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

A?

B@>

C->

D#>

Attempts:

3 left

💡 Hint

Common Mistakes

Using @> which checks for containment of a JSONB object, not a key.

Using -> which extracts JSONB object fields, not checks existence.

The ? operator checks if the JSONB column contains the specified key.

2fill in blank

medium

Complete the code to find rows where the JSONB column 'info' contains the key 'age'.

PostgreSQL

SELECT id FROM profiles WHERE info [1] 'age';

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

A@>

B?

C?&

D?|

Attempts:

3 left

💡 Hint

Common Mistakes

Using ?| or ?& which check for multiple keys, not a single key.

Using @> which checks for JSONB containment, not key existence.

The ? operator checks for a single key's existence in JSONB.

3fill in blank

hard

Fix the error in the code to check if the JSONB column 'attributes' contains the key 'color'.

PostgreSQL

SELECT * FROM items WHERE attributes [1] 'color';

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

A#>

B->

C@>

D?

Attempts:

3 left

💡 Hint

Common Mistakes

Using -> which extracts JSONB values but does not check key existence.

Using @> which checks if JSONB contains another JSONB object.

The correct operator to check key existence is ?. Others extract or compare JSONB data differently.

4fill in blank

hard

Complete the code to check if the JSONB column 'settings' contains both keys 'dark_mode' and 'notifications'.

PostgreSQL

SELECT * FROM user_prefs WHERE settings [1] ARRAY['dark_mode', 'notifications'] ;

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

A?&

B?|

C;

Attempts:

3 left

💡 Hint

Common Mistakes

Using ?| which checks if any key exists, not all keys.

Adding a semicolon inside the WHERE clause causing syntax error.

The ?& operator checks if all keys in the array exist in the JSONB column. No extra symbol is needed after the operator.

5fill in blank

hard

Fill both blanks to find rows where the JSONB column 'config' contains either 'auto_save' or 'backup' keys.

PostgreSQL

SELECT * FROM documents WHERE config [1] ARRAY['auto_save', [2]] ;

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

A?|

B'backup'

D'autosave'

Attempts:

3 left

💡 Hint

Common Mistakes

Using ?& which requires all keys to exist, not any.

Forgetting quotes around keys causing syntax errors.

Adding a semicolon inside the WHERE clause.

The ?| operator checks if any key in the array exists in the JSONB column. The keys must be quoted strings. No extra symbol is needed after the operator.