Master SQL Subqueries | Single-row | Multi-row | Correlated | Uncorrelated Subqueries

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In this tutorial, we dive deep into SQL Subqueries - what they are, the different types, real-world examples, and most importantly, how to write efficient subqueries that boost your database performance!

Notes: https://github.com/nakulmitra/database-postgresql/blob/master/notes/subqueries.md

What You’ll Learn:
- What are Subqueries in SQL?
- Types of Subqueries: Single-row, Multi-row, Correlated, and Uncorrelated
- Practical Examples Explained
- How to Optimize Subqueries for Faster Performance
- Common Mistakes to Avoid with Subqueries

Key Concepts Covered:
- Using subqueries to filter, aggregate, and transform data
- Real-world SQL use cases

Sample Queries Included:
- Find employees earning above average salary
- List departments based on salary conditions
- Correlated subqueries example
- Aggregating results with nested subqueries

Timestamp:
00:00 - Introduction
00:17 - What are Subqueries?
02:23 - Single-row Subquery
03:13 - Multi-row Subquery
05:59 - Correlated Subquery
09:25 - Uncorrelated Subqueries (Using Subqueries with Aggregates)
14:50 - Writing Efficient Subqueries
15:42 - Common Mistakes to Avoid
16:19 - Summary

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