[Solved] Given the JSONB column data with value '{"name": "Alice", "details": {"age": 30}}', what will be the result of this query?SELECT jsonb_set(data, '{details,age}', '31', false) FROM table; | PostgreSQL

PostgreSQL - JSON and JSONB

Given the JSONB column data with value '{"name": "Alice", "details": {"age": 30}}', what will be the result of this query?

SELECT jsonb_set(data, '{details,age}', '31', false) FROM table;

A{"name": "Alice", "details": {"age": 31}}

B{"name": "Alice", "details": {"age": "31"}}

C{"name": "Alice", "details": {"age": 30}}

D{"name": "Alice", "details": {"age": null}}

Step-by-Step Solution

Solution:

Step 1: Understand jsonb_set parameters
The function jsonb_set updates the value at path '{details,age}' to '31' (a JSON string) because the new value is given as text, not as a number.
Step 2: Check the effect of the 'create_missing' flag
The last parameter is false, so it updates existing key without creating new ones. The age key is updated to the string '31', not the number 31.
Final Answer:
{"name": "Alice", "details": {"age": "31"}} -> Option B
Quick Check:
jsonb_set updates value as text unless cast [OK]

Quick Trick: jsonb_set inserts text values unless cast to JSONB [OK]

Common Mistakes:

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Given the JSONB column data with value '{"name": "Alice", "details": {"age": 30}}', what will be the result of this query?