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Want to Learn Data Analysis? | 매거진에 참여하세요

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publish_date : 25.07.31

Want to Learn Data Analysis?

#SQL #Beginner #Define #Concept #Tech #Words #NoSQL

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Want to Learn Data Analysis? Start Here.

For many of us in business or planning roles, data extraction once felt like someone else’s job.

Our responsibility was to analyze and report—not write queries.

But as I dug deeper into data analysis, I realized something important: being able to extract your own data is a superpower.

It’s where your intent, your hypothesis, and your logic come to life. That’s why I now tell every new team member:

“Learn SQL. Learn how to get the data yourself.”

Whether you're aiming to build a product strategy, optimize operations, or explore a career in data, this guide will help you understand why SQL is essential—and how to get started.


Why SQL Is the Language of Data Analysis

Structured Query Language (SQL) is the most widely used tool for managing and analyzing structured data.

If you're using a relational database—think rows and columns—SQL is how you ask questions.

It lets you:

  • Extract relevant insights from massive datasets

  • Clean and transform raw information

  • Build reports and dashboards that drive decisions

SQL vs NoSQL: What's the Difference?


Feature

SQL (Relational DB)

NoSQL (Non-relational DB)

Schema

Fixed, pre-defined

Flexible, schema-less

Data Structure

Tables (rows and columns)

JSON, documents, key-value, graph, etc.

Scaling

Vertical (scale-up)

Horizontal (scale-out, distributed systems)

Use Cases

Financial systems, inventory, CRM

Real-time analytics, unstructured content

Tip: Learn SQL first. NoSQL is easier to understand later when you know the foundations of structured data.

Popular SQL Variants for Analysts

Platform

Best For

Notes

MySQL

Beginners, small web apps

Lightweight, easy to install

PostgreSQL

Complex queries, large datasets

Open-source, powerful features, strong ecosystem

SQL Server

Enterprise, Microsoft stack

Great integration with BI tools (Excel, Power BI)

SQL vs R vs Python: Which Should You Learn?

Tool

Strengths

SQL

Data querying, filtering, joining

R

Statistics, modeling, visualizations

Python

Automation, machine learning, flexible ETL

💡 Most analysts combine all three.

Starter Projects to Practice SQL

Here are some beginner-friendly ideas:

  • Sales Analysis: Track trends and KPIs from a fictional store

  • Customer Segmentation: Group buyers by behavior or region

  • Churn Prediction: Spot patterns in user retention

  • Inventory Optimization: Analyze stock vs. demand

  • Campaign Evaluation: Measure marketing performance

Core Concepts You Need to Understand

  • Databases: Structured sets of data stored electronically

  • Tables: Collections of rows (records) and columns (attributes)

  • Schemas: Definitions of how data is organized

  • Queries: Instructions written in SQL to interact with data

3 Must-Know SQL Operations

  1. SELECT

    • Retrieve data from one or more tables

    • Filter using WHERE, sort with ORDER BY, limit rows with LIMIT

  2. INSERT / UPDATE / DELETE

    • Insert new records, update existing ones, or remove outdated entries

  3. JOIN

    • Combine data from multiple tables

    • Learn INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN

Intermediate to Advanced SQL Techniques

1. Subqueries

Write a query inside another query to filter or aggregate data.

2. Aggregations & Grouping

Use functions like SUM(), AVG(), COUNT(), and GROUP BY to generate summaries.

Example:

SELECT customer_id, COUNT(*) AS total_orders FROM orders GROUP BY customer_id;

3. Data Cleaning with SQL

  • Remove Duplicates: Using DISTINCT or GROUP BY

  • Handle Missing Values: Use IS NULL, COALESCE()

  • Standardize Values: Convert case, format dates, fix typos

Real-World SQL: The Gaming Industry

In online games, SQL powers player data, match histories, scores, inventories, and more.

With hundreds of players online simultaneously, SQL ensures:

  • - Real-time data consistency

  • - Fast access to game assets

  • - Personalized content delivery

SQL isn’t just for banks or CRMs—it runs behind the scenes of dynamic, immersive environments.

Using SQL in Analytics Workflows

1. Data Cleaning

Fix inconsistencies, remove nulls, standardize formats

2. Data Transformation

Calculate new fields (e.g., revenue = unit × price), pivot data, join tables

3. Exploratory Data Analysis (EDA)

Use SQL to summarize, filter, and inspect distributions

4. Reporting & Visualization

  • Feed cleaned SQL data into Tableau, Power BI, or Excel

  • Build interactive dashboards and automate reports

Final Words: SQL as Your Compass

If you're just getting started with data analysis, SQL is the map and compass.

It connects questions to insights—and makes you a more self-sufficient, valuable contributor.

It may seem overwhelming at first, but start with the basics, build projects, and keep practicing.

You'll be surprised how fast you start speaking the language of data.