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SQL: Breaking down Advance sql components — Part 1
Introduction
As modern databases become more complex, mastering advanced SQL techniques is essential for data analysts, engineers, and developers to efficiently solve sophisticated business problems.
In this article I will dive deep into advanced SQL components, providing a comprehensive overview of key functionalities such as joins, window functions, advanced filtering techniques, set operations, subqueries, and Common Table Expressions (CTEs).
Let’s explore these components with examples to enhance your SQL proficiency —
1. JOINS
Joins are used to combine rows from two or more tables based on a related column between them. They allow you to retrieve data that spans multiple tables, enabling comprehensive analysis and reporting.
• self join
— Table is joined to itself, for scenarios where data within the same table needs to be compared
• cross join
— Combines all rows from one table with all rows from another table, resulting in a Cartesian product, for scenarios like generating all possible combinations of two datasets.
-- self join
SELECT e1.employee_id AS employee_1…