6 modules · Self-paced · Practice included

SQL and Database Management

Query relational data, protect analytical grain, inspect execution plans and deliver a checked SQL project.

18 published lessons17h 30m suggested study2 free introductory modules

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Every module includes three substantial lessons, downloadable source files, practical exercises, explained solutions and a knowledge check. Modules marked free are available under the current public access rules. Protected self-learning modules are free after registration and email verification. Publication, prerequisites and explicit private-access rules still apply.

01Free module

Relational Databases and SQL Fundamentals

Inspect schemas and keys, query an explicit projection and test relationships.

3 lessons · 2h 55m suggested

A table/grain relationship diagram
An explicit ordered SELECT
A checked key and orphan audit

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02Free module

Filtering, Sorting, and Aggregation

Build bounded populations and summaries with correct denominators.

3 lessons · 2h 55m suggested

A written and tested date/population filter
Channel totals with row/order reconciliation
A documented group-threshold comparison

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03Free · verified account

Joins and Subqueries

Choose relationships deliberately and preserve unmatched evidence.

3 lessons · 2h 55m suggested

A join-cardinality reconciliation
An EXISTS membership query and counterexample
An unmatched-product test

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Join with a cardinality contract · Verified account
Use EXISTS for membership questions · Verified account
Preserve unmatched categories with LEFT JOIN · Verified account

04Free · verified account

Common Table Expressions and Window Functions

Make analytical stages readable and preserve rows with explicit window definitions.

3 lessons · 2h 55m suggested

A CTE grain diagram
A reproducible tie-ranking comparison
A running total with an explicit frame

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Build a readable analytical stage with a CTE · Verified account
Distinguish row numbering from ranking ties · Verified account
Declare a running-total window frame · Verified account

05Free · verified account

Database Design and Query Optimization

Model historical facts, use constraints and compare query plans without unsupported speed claims.

3 lessons · 2h 55m suggested

A normalized/historical fact model
A before/after plan with equal results
A responsible query-access checklist

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Normalize relationships without losing history · Verified account
Inspect an index access path · Verified account
Use responsible access and workload review · Verified account

06Free · verified account

Practical SQL Projects and Interview Challenges

Answer a reporting brief, reconcile independent formulations and defend a query.

3 lessons · 2h 55m suggested

A complete reporting query set
An independently reconciled evidence note
A scored interview explanation and counterexample

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Translate a reporting brief into a metric contract · Verified account
Reconcile through an independent query path · Verified account
Explain and review a SQL interview answer · Verified account

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