[Solved] Identify the error in this query:SELECT * FROM employees WHERE department_id IN SELECT id FROM departments WHERE name = 'HR'; | PostgreSQL

PostgreSQL - Subqueries in PostgreSQL

Identify the error in this query:

SELECT * FROM employees WHERE department_id IN SELECT id FROM departments WHERE name = 'HR';

AMissing parentheses around the subquery after IN.

BUsing IN instead of EXISTS.

CSubquery returns multiple columns.

Ddepartment_id cannot be compared with id.

Step-by-Step Solution

Solution:

Step 1: Check syntax for subquery with IN
The subquery must be enclosed in parentheses after the IN keyword.
Step 2: Identify missing parentheses causing syntax error
The query lacks parentheses around the subquery, causing invalid syntax.
Final Answer:
Missing parentheses around the subquery after IN. -> Option A
Quick Check:
Subquery must be in parentheses after IN [OK]

Quick Trick: Always wrap subqueries in parentheses after IN [OK]

Common Mistakes:

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Identify the error in this query: