[Solved] Given the table users(id SERIAL PRIMARY KEY, data JSONB) with data:{"name": "Alice", "age": 30} in the data column, what does this query return?... | PostgreSQL

PostgreSQL - Advanced Features

Given the table users(id SERIAL PRIMARY KEY, data JSONB) with data:
{"name": "Alice", "age": 30} in the data column, what does this query return?

SELECT data->>'name' FROM users WHERE data->>'age' = '30';

AReturns all data rows regardless of age.

BReturns the age 30 as a number.

CReturns the name 'Alice' for users aged 30.

DReturns an error due to wrong JSON syntax.

Step-by-Step Solution

Solution:

Step 1: Understand JSONB operators in the query
The operator ->> extracts JSON object field as text. The WHERE clause filters rows where age equals '30' as text.
Step 2: Analyze query result
The SELECT returns the 'name' field as text for rows matching age '30'. So it returns 'Alice'.
Final Answer:
Returns the name 'Alice' for users aged 30. -> Option C
Quick Check:
data->>'name' with age filter = 'Alice' [OK]

Quick Trick: ->> extracts text from JSONB fields [OK]

Common Mistakes:

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Given the table users(id SERIAL PRIMARY KEY, data JSONB) with data: