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Learn a concept by watching it work, then practice it. Each guide is one idea, shown with a runnable demo.
SQL
Single-table basics
- Row Filteringsoon
- Sorting and Limitingsoon
- NULL Handlingsoon
- Select and Projectionsoon
- Column and Table Aliasessoon
- Comparison and Logical Predicatessoon
- Distinct Rowssoon
Expressions and functions
- Conditional Logicsoon
- Date and Time Manipulationsoon
- String Functionssoon
- Numeric Functionssoon
- Type Castingsoon
- Pattern Matchingsoon
Aggregation
- Group By and Aggregationsoon
- Filtering Groups with HAVINGsoon
- Deduplicationsoon
- Conditional Aggregationsoon
- Grouping Sets, Rollup, and Cubesoon
Joins
Subqueries and CTEs
- Subqueriessoon
- Common Table Expressionssoon
- Scalar Subqueriessoon
- Correlated Subqueriessoon
- Recursive CTEssoon
- Lateral Joinssoon
Window functions
- Window Functionssoon
- Window Rankingsoon
- Running Totals and Moving Aggregatessoon
- Period-over-Period with LAG and LEADsoon
- Window Value Functionssoon
- Window Framessoon
Advanced and specialized
- Pivot and Unpivotsoon
- JSON and Semi-Structured Datasoon
- Arrays and Unnestsoon
- Upsert and Mergesoon
Data modeling
Relational foundations
- Primary Keyssoon
- Foreign Keyssoon
- Uniqueness Constraintssoon
- Relationship Cardinalitysoon
- Many-to-Many Modeling
Schema design
Dimensional modeling
- Fact vs Dimension Rolessoon
- Fact Table Grain
- Surrogate Keyssoon
Dimension patterns
- Conformed Dimensionssoon
- Degenerate Dimensionssoon
- Bridge Tablessoon
Change and time
- Slowly Changing Dimension Type 2
- Snapshot Fact Typessoon
- Temporal Validity Columnssoon