[Solved] Given the table items with a json column data storing '{"a":1, "b":2}', what will this query return?SELECT data @> '{"a":1}'::jsonb FROM items; | PostgreSQL

PostgreSQL - JSON and JSONB

Given the table items with a json column data storing '{"a":1, "b":2}', what will this query return?

SELECT data @> '{"a":1}'::jsonb FROM items;

AError because <code>data</code> is json, but query uses jsonb operator

BTrue for rows where <code>data</code> contains key "a" with value 1

CFalse for all rows because <code>data</code> is json, not jsonb

DReturns all rows regardless of content

Step-by-Step Solution

Solution:

Step 1: Understand operator compatibility
The @> operator is defined for jsonb types, not for json. Using it on a json column causes an error.
Step 2: Analyze the query
The query tries to use @> on data which is json, but the right side is cast to jsonb. This mismatch causes a type error.
Final Answer:
Error because data is json, but query uses jsonb operator -> Option A
Quick Check:
jsonb operator on json column = Error [OK]

Quick Trick: jsonb operators need jsonb columns, not json [OK]

Common Mistakes:

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Given the table items with a json column data storing '{"a":1, "b":2}', what will this query return?