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SQL & database
internals, in depth.
Read it, watch it, visualize every table step, run real SQL in WebAssembly.
- 180
- Topics
- 36
- Simulators
- 18
- Builds
- 36
- Videos
- 720
- Questions
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Logical Query Execution Pipeline (FROM → WHERE → SELECT → ORDER BY → LIMIT)
Clause Pipeline
Step through a multi-clause SQL query at the table level. Watch rows flow from the base table through predicate filtering, expression projection, sorting, and Top-N pagination.
Step 1 / 8
Timeline
Invariant & State
Relation initialized with 6 tuples across schema (order_id, customer, status, total_cents, created_at) — preset: Paid Orders ≥ $120 Ordered by Total DESC LIMIT 3.
🔗 Live Pointer & State Transition Graph — Logical Query Execution Pipeline (FROM → WHERE → SELECT → ORDER BY → LIMIT)
Active Pointer
Jump/Transition
Matched/Optimal
[0]101:paidTuple #0
[1]102:pending
[2]103:paid
[3]104:refunded
[4]105:paid
[5]106:paid
Input Tuples
6
Columns
5
Preset Mode
orders
Pipeline Stage
1. Initial Scan
[Step 1] Initialized Logical Query Execution Pipeline (FROM → WHERE → SELECT → ORDER BY → LIMIT) (Paid Orders ≥ $120 Ordered by Total DESC LIMIT 3) with 6 base rows.
In every lesson
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Hand-picked videos
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18 from-scratch builds
Mini Relational Tuple Filter & Projection EngineE-Commerce Schema with Referential Integrity & Upsert PipelineMulti-Table Order, Payment & Shipment Reconciliation EngineMulti-Dimensional Revenue, Cohort & Funnel Aggregation SuiteBill-of-Materials & Social Graph Reachability EngineClickstream Sessionizer, Streak Tracker & Rolling Window AnalyzerNormalize a Legacy Flat Spreadsheet into a 3NF/BCNF SystemStar Schema with Automated SCD Type 2 Dimension PipelineComplete SaaS Analytics EngineB+Tree Page Simulator & Automated Workload Index AdvisorInteractive EXPLAIN Plan Bottleneck Detector & Query RewriterImplement & Benchmark Nested Loop, Hash Join & Sort-Merge JoinDual-Session Concurrency Anomaly & Isolation VerifierMulti-Version Tuple Store with Snapshot Isolation & Vacuum GC8KB Slotted Page + Write-Ahead Log Crash Recovery SimulatorColumnar RLE/Dictionary Encoder with Zone-Map Predicate PushdownConsistent-Hash Shard Router with Partition Pruning & Scatter-GatherEnd-to-End Slow Query Diagnostic & Optimization Clinic
Curriculum
Relational Foundations & Core Querying
1.1
The Relational Model, Tables & SELECT Foundations
1.2
DDL, Schema Constraints & DML Mutations
1.3
Relational Algebra & Multi-Table Joins
Aggregations, Subqueries, CTEs & Window Functions
2.1
Grouping, Aggregations & Multi-Dimensional Rollups
2.2
Subqueries, Correlated Queries, Lateral Joins & CTEs
2.3
Window Functions & Analytical SQL Mastery
Data Modeling, Normalization & Schema Architecture
3.1
Relational Data Modeling & Normalization (1NF to BCNF/5NF)
3.2
Dimensional Modeling & Analytical Schema Design
3.3
Advanced SQL Patterns, Temporal Queries & Programmability
Indexing, Query Planner & Execution Engine
4.1
B+Tree Indexes & Access Path Mechanics
4.2
The Query Planner, Cost-Based Optimizer & EXPLAIN
4.3
Physical Join Algorithms & Execution Pipelines
Transactions, Concurrency Control, MVCC & Storage Internals
5.1
ACID Transactions, Concurrency Anomalies & Isolation Levels
5.2
Locking, MVCC Internals & Vacuuming
5.3
Storage Engine Internals: Pages, Buffer Pool, WAL & LSM-Trees