SQL for Data Science Fundamentals
Chapter 1: Introduction to Databases and SQL
What is a Relational Database?
Tables, Columns, and Rows
Understanding Data Types
What is SQL (Structured Query Language)?
Setting Up Your Environment (Optional)
Chapter 2: Retrieving Data with SELECT
The Basic SELECT Statement
Selecting Specific Columns
Selecting All Columns
Using Aliases for Columns
Limiting Query Results
Hands-on Practical: Writing Basic SELECT Queries
Chapter 3: Filtering and Sorting Data
Introduction to Filtering with WHERE
Comparison Operators (=, <>, <, >, <=, >=)
Filtering with AND, OR, NOT
Filtering with IN and BETWEEN
Handling NULL Values
Pattern Matching with LIKE
Sorting Results with ORDER BY
Hands-on Practical: Filtering and Sorting Queries
Chapter 4: Aggregating Data
Introduction to Aggregate Functions
Counting Rows with COUNT
Calculating Sums with SUM
Calculating Averages with AVG
Finding Minimum and Maximum Values with MIN/MAX
Grouping Data with GROUP BY
Filtering Groups with HAVING
Hands-on Practical: Aggregation and Grouping
Chapter 5: Combining Data from Multiple Tables
Why Combine Data?
Understanding Primary and Foreign Keys
Introduction to SQL JOINs
Using INNER JOIN
Joining Multiple Tables
Using Aliases for Tables
Hands-on Practical: Writing INNER JOIN Queries
Retrieving Data with SELECT
With an understanding of relational database structure from the previous chapter, we now focus on extracting data. The SELECT statement is the fundamental tool for querying information stored in tables.
This chapter introduces the core syntax and usage of SELECT. You will learn to:
- Retrieve specific columns from a table.
- Select all available columns.
- Use aliases to provide temporary, readable names for columns in your query results.
- Control the number of rows returned using the
LIMITclause (or its database-specific equivalent).
Practical exercises are included throughout the sections to help you apply these concepts.
Sections
2.1 The Basic SELECT Statement
2.2 Selecting Specific Columns
2.3 Selecting All Columns
2.4 Using Aliases for Columns
2.5 Limiting Query Results
2.6 Hands-on Practical: Writing Basic SELECT Queries
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