Data Workshop & SQL Analytics Studio

Query, join, filter, and analyze local CSV, JSON, and Parquet datasets with DuckDB-WASM.

Data Workshop & SQL Analytics Studio

Query, join, filter, and analyze local CSV, JSON, and Parquet datasets with DuckDB-WASM.

How It Works

1
Select Your File
Choose the file you want to process; your data is processed locally without uploads.
2
Configure Options
Adjust conversion, compression, or processing settings to suit your needs.
3
Process & Download
Run the task client-side in your browser and download the processed result.
Concept & Knowledge Hub

Local SQL Data Workshop: In-Browser DuckDB Analytics for CSV, JSON & Parquet

Modern analytical datasets often originate in disparate formats—such as transactional CSV exports, nested JSON event payloads, and column-oriented Apache Parquet files. Traditional analysis typically requires spinning up remote databases or uploading gigabytes of sensitive proprietary data to third-party cloud analytics platforms. The Local SQL Data Workshop runs an enterprise-grade SQL OLAP database engine directly inside your browser sandbox using DuckDB-WASM and Web Workers.

You can load multiple independent tabular files simultaneously into ephemeral browser memory (:memory:), inspect schema column types and null counts, join tables across different file formats using standard ANSI/DuckDB SQL syntax, and execute analytical aggregations (GROUP BY, window functions, CTEs) in milliseconds. Advanced CSV ingestion options preserve leading zeroes (e.g. employee IDs and phone numbers), financial decimal strings (e.g. currency amounts), 64-bit integer precision, and ISO-8601 UTC timestamps without floating-point IEEE 754 precision loss. Large query result sets are displayed in a high-performance virtualized grid with dedicated controls to cancel long-running queries.

All database indexing, SQL execution, and table transformations occur 100% locally on your device. The analytical engine operates with external network access disabled; no file contents, schema names, or query strings ever leave your computer. Clean analytical outputs can be safely exported to Apache Parquet, CSV (with automated formula injection defense against spreadsheet macro attacks), or JSON.

Core Architecture & Mathematical Formula

DuckDB-WASM OLAP Engine: In-Memory Virtual File System (VFS) + Vectorized Execution + Web Worker Threading

Tabular files are registered into DuckDB's in-memory catalog via typed zero-copy Arrow memory buffers; vectorized execution delivers native SIMD analytics on multicore clients.

Best Practices & Essential Guidelines

  • Preserve String Identifiers: Enable the 'Preserve Leading Zeros & Types' toggle for CSV datasets containing postal codes, account numbers, or product SKUs to prevent silent numerical type conversion.
  • Leverage Native Parquet Ingestion: Use Apache Parquet for large tabular datasets to benefit from columnar compression, dictionary encoding, and instant query execution.
  • Cancel Long-Running Queries Safely: If a complex Cartesian join or intensive regex consumes high CPU, click 'Cancel Query' to immediately terminate the worker thread and preserve browser responsiveness.
  • Sanitize Exported Spreadsheets: Keep the CSV formula shield enabled when exporting analytical results to prevent CSV formula injection attacks (=, +, -, @) when opened in desktop spreadsheet applications.

Frequently Asked Questions (FAQ)

What file formats can I query and analyze in the SQL Data Workshop?
You can import and query CSV/TSV, JSON (newline-delimited and record arrays), Apache Parquet files, and Excel spreadsheets (via SheetJS). You can seamlessly execute SQL JOIN operations across different formats in a single query.
Are my database files or query contents uploaded to any cloud server?
No. The SQL engine runs 100% locally inside your web browser via DuckDB WebAssembly (WASM). All queries execute in a background Web Worker utilizing local device RAM. Zero bytes are transmitted to any remote server.
Can I cancel a query if it takes too long or freezes the browser?
Yes. The workshop runs in an isolated background Web Worker with active cancellation support. Clicking 'Cancel Query' sends an immediate interrupt signal and terminates the worker if necessary, restoring a clean session without page reloads.
How does the workshop prevent CSV formula injection in exported files?
When exporting to CSV, any text field beginning with dangerous spreadsheet formula triggers (=, +, -, @, or \t) is automatically prefixed with an apostrophe (') when the formula shield is active, neutralizing automated code execution in Microsoft Excel or Google Sheets.