SQL Learning Path and Resources

Aug 7, 2024

SQL Learning Roadmap

Introduction

  • SQL is essential for interacting with relational databases.
  • Different roles require different levels of SQL expertise:
    • Basic SQL
    • Intermediate SQL
    • Advanced SQL
    • SQL for Developers

Structure of the Video

  1. Prerequisites
  2. Basic SQL
  3. Intermediate SQL
  4. Advanced SQL
  5. SQL for Developers

Prerequisites

  • SQL is used to interact with relational databases where data is stored.
  • Most popular relational databases:
    • Oracle
    • MySQL
    • Microsoft SQL Server
    • PostgreSQL
  • Choose any RDBMS for learning as SQL syntax is largely consistent across platforms.
  • Recommended: PostgreSQL for beginners (free, lightweight).
  • Install a database and an IDE tool (e.g., SQL Developer, MySQL Workbench, PG Admin).
  • Basic understanding of data analytics, data science, and software engineering is beneficial.

Learning Basic SQL

Key Concepts

  1. Understanding Relational Databases

    • What is RDBMS?
    • Data storage and schema.

  2. SQL Commands

    • Categories: DDL, DML, DCL, TCL, DQL.
    • Important commands: DROP, DELETE, TRUNCATE.

  3. Data Types

    • String, Integer, Date, Float/Decimal, and Boolean (check RDBMS support).
    • Identity columns for auto-increment.

  4. Constraints

    • Primary and foreign key constraints.
    • Check, Not Null, Unique, Default constraints.

  5. Normalization

    • Different normal forms and their importance.

  6. Operators

    • Arithmetic, logical, comparison, and union operators.

  7. SQL Clauses

    • Distinct, Order By, Limit/Top clauses.

  8. Joins

    • Using INNER JOIN to fetch data from multiple tables.

Resources for Learning Basic SQL

  • Install PostgreSQL and follow setup videos.
  • Watch SQL Basics tutorial videos.
  • Use W3Schools for syntax references.

Practice Platforms

  • Strata Scratch
  • LeetCode
  • Data Lemur

Job Opportunities

  • Business Analyst
  • Junior Analyst
  • Software Engineer (1-3 years)

Learning Intermediate SQL

Key Concepts

  • Jobs Targeted: Data Analyst, Data Scientist.
  • Essential Concepts:
    • GROUP BY and HAVING clauses.
    • Aggregate functions: MIN, MAX, AVG, SUM, COUNT.
    • Order of execution.
    • Subqueries.
    • CTE (Common Table Expressions).
    • Various joins: outer joins, self joins.
    • Inbuilt functions: string and date functions.
    • Window Functions: RANK, DENSE_RANK, ROW_NUMBER, LEAD, LAG.
    • Views and their uses.

Resources for Learning Intermediate SQL

  • Watch tutorial videos on various topics (links provided).
  • Use W3Schools for additional examples.

Practice Platforms

  • Strata Scratch
  • LeetCode
  • Data Lemur
  • SQL case studies from Data with Danny.

Learning Advanced SQL

Key Concepts

  • Jobs Targeted: Data Engineer, ETL Developer.
  • Additional Concepts:
    • Recursive SQL queries.
    • Pivot tables and crosstabs.
    • Materialized views, stored procedures, and user-defined functions.

Resources for Learning Advanced SQL

  • Tutorial videos for each advanced concept (links provided).

Practice Platforms

  • Strata Scratch
  • LeetCode
  • Data Lemur
  • Case studies from Data with Danny.

Becoming a Database Developer or SQL Developer

Key Concepts

  • Jobs Targeted: Database Developer, SQL Developer.
  • Essential Skills:
    • Indexes and performance improvement.
    • Triggers, temporary tables, and dynamic SQL execution.
    • PL/SQL concepts: variables, cursors, arrays, loops, and exception handling.
    • Performance tuning techniques.

Resources for Learning

  • Various blogs (links provided) for deeper understanding of advanced concepts.

Conclusion

  • This roadmap provides a clear path for learning SQL tailored to various roles.
  • Important to practice regularly and utilize available resources effectively.
  • Join communities and forums for additional support and learning.