[Solved] What will be the result of this query?SELECT data->'items'->>0 FROM orders WHERE id=5;Assuming data contains JSON array under key 'items'. | PostgreSQL

PostgreSQL - JSON and JSONB

What will be the result of this query?
SELECT data->'items'->>0 FROM orders WHERE id=5;
Assuming data contains JSON array under key 'items'.

ANULL

BJSON object of the first element in 'items' array

CError due to invalid operator usage

DText value of the first element in 'items' array

Step-by-Step Solution

Solution:

Step 1: Analyze operator chaining
data->'items' extracts the JSON array as JSON, then ->>0 extracts the first element as text.
Step 2: Understand array indexing with ->>
Using ->>0 extracts the element at index 0 as text, so the output is the text value of the first array element.
Final Answer:
Text value of the first element in 'items' array -> Option D
Quick Check:
Chained -> and ->> extract nested JSON text [OK]

Quick Trick: Chain -> for JSON, ->> for text extraction [OK]

Common Mistakes:

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What will be the result of this query?