📊 SQL for Beginners with Databases and Queries

Why Spreadsheets and Text Files Stop Working, and What a Database Fixes

19 min

Relational Thinking: Tables, Rows, Columns, and Data Types

14 min

Getting Set Up: Installing PostgreSQL and Running Your First Query

16 min

The SQL Family: DDL vs DML, and What Actually Happens When You Hit Run

16 min

CREATE TABLE and INSERT: Building the Sample Database You Will Use All Course

14 min

Primary Keys: Natural vs Surrogate, and Why Every Table Needs an Identity

16 min

Foreign Keys and Relationships: One-to-One, One-to-Many, Many-to-Many

15 min

Constraints as Free Bug Prevention: NOT NULL, UNIQUE, CHECK, DEFAULT

17 min

Normalization Without the Jargon: 1NF, 2NF, 3NF Explained With One Messy Table

13 min

Denormalization: When Breaking the Rules Is the Right Call

16 min

ER Diagrams: Designing a Complete Schema From a Real World Brief

15 min

SELECT: Columns, Aliases, and Expressions

12 min

WHERE: Comparison and Logical Operators

18 min

IN, BETWEEN, LIKE, and the NULL Trap That Catches Everyone

17 min

ORDER BY, LIMIT, and OFFSET

17 min

ORDER BY, LIMIT, and OFFSET

18 min

Aggregate Functions: COUNT, SUM, AVG, MIN, MAX

13 min

Splitting Data Into Buckets

19 min

HAVING vs WHERE: The Difference People Get Wrong in Interviews

13 min

Grouping by Multiple Columns, and the Traps That Come With It

14 min

The Real Order of Execution: Why SQL Does Not Run Top to Bottom

12 min

Why Your Data Lives in Pieces, and What a JOIN Really Does

19 min

INNER JOIN and LEFT JOIN: The Two You Will Use 90% of the Time

19 min

RIGHT, FULL, CROSS, and SELF Joins

15 min

Joining Three or More Tables, and Joining With Aggregation

19 min

Subqueries: Scalar, IN, EXISTS, and Correlated

19 min

Derived Tables and Set Operations: UNION, INTERSECT, EXCEPT

19 min

Window Functions: OVER, PARTITION BY, and How They Differ From GROUP BY

19 min

Ranking Functions: ROW_NUMBER, RANK, DENSE_RANK, NTILE

19 min

Aggregate Window Functions and Frames: Running Totals and Moving Averages

14 min

Offset Functions: LAG and LEAD for Comparing Rows to Their Neighbours

12 min

Common Table Expressions: Making a Monster Query Readable

12 min

Recursive CTEs: Org Charts, Category Trees, and Generated Series

17 min

Reading the Plan: EXPLAIN and EXPLAIN ANALYZE

16 min

Indexes: How B-Trees Work, When They Help, and When They Slow You Down

16 min

Slow Query Patterns and How to Rewrite Them

13 min

Transactions, ACID, and the Money Transfer Example

15 min

Views and Stored Logic: Reusing Queries Safely

14 min

Capstone: Design, Populate, Query, and Optimize a Complete Database

19 min