Learning Paths / Learn SQL

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beginner
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Learn SQL

Query relational databases confidently — from SELECT and JOINs to CTEs, window functions, and query optimization.

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Querying Basics

  1. 1

    SELECT

    Query rows and columns from tables with filtering and sorting

  2. 2

    WHERE Clause

    Filter rows with conditions, operators, and NULL handling

  3. 3

    CRUD Operations

    Create, read, update, and delete rows with INSERT, UPDATE, and DELETE

Combining Data

  1. 1

    Joins

    Combine rows from related tables with INNER, LEFT, and other joins

  2. 2

    GROUP BY

    Aggregate rows with COUNT, SUM, AVG, and HAVING filters

  3. 3

    Subqueries

    Nest queries inside other queries to filter, compute, and compare

Advanced Queries

  1. 1

    Common Table Expressions

    Name intermediate result sets with WITH for readable, reusable queries

  2. 2

    Window Functions

    Compute running totals, rankings, and comparisons across row windows

  3. 3

    Views

    Save queries as reusable virtual tables for cleaner, consistent access

Performance & Integrity

  1. 1

    Transactions

    Group statements into atomic, consistent, isolated, durable units of work

  2. 2

    Indexes

    Speed up queries with B-tree indexes and when to add them

  3. 3

    Query Optimization

    Read execution plans and tune queries for speed at scale