[Solved] Why do we use subqueries in SQL?SELECT * FROM employees WHERE department_id IN (SELECT id FROM departments WHERE location = 'NY'); | SQL

SQL - Subqueries

Why do we use subqueries in SQL?
SELECT * FROM employees WHERE department_id IN (SELECT id FROM departments WHERE location = 'NY');

ATo use the result of one query inside another for filtering or comparison

BTo speed up the database server automatically

CTo create new tables from existing ones

DTo change the database schema

Step-by-Step Solution

Solution:

Step 1: Understand the role of subqueries
The subquery inside the IN clause fetches department IDs located in 'NY'.
Step 2: See how the main query uses subquery results
The main query selects employees whose department_id matches those IDs from the subquery.
Final Answer:
To use the result of one query inside another for filtering or comparison -> Option A
Quick Check:
Subqueries help filter data using other query results [OK]

Quick Trick: Subqueries let queries talk to each other inside SQL [OK]

Common Mistakes:

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