Guides
Practical walkthroughs for getting real work done with data files. Every SQL example has been run against the tool, so the queries and the row counts are what you will actually see.
Start here
How to analyse a CSV file in three steps
Drop a file in, look at what you have, then ask it questions. The beginner walkthrough, plus the four things that trip everyone up first time.
Turn any file into a SQL table
How files become queryable tables: where the alias letter comes from, how columns get named, and how to query up to 26 files at once.
Run SQL without installing a database
No server, no admin rights, no ticket. What SQL is supported, what deliberately is not, and why this suits locked-down machines and learning.
Everyday tasks
How to join two CSV files using SQL
Combine two files on a shared column with a real JOIN — no VLOOKUP. Includes the four reasons a join returns zero rows, and how to fix each.
How to clean and export a data extract
SQL recipes for whitespace, inconsistent case, duplicates, blanks and outliers — then exporting the clean version without touching the original.
How to run SQL on an Excel spreadsheet
Your formulas translated to SQL, plus the Excel quirks — merged cells, two-row headers, numbers stored as text — that quietly break imports.
Formats and conversion
How to open a Parquet file offline
Read and query a .parquet file without Python, Spark or DuckDB — and convert it to CSV or Excel while you are there.
Convert between CSV, JSON, Excel and Parquet
Every pairing in three steps, including converting only the rows and columns you need — and exactly what survives the trip.
How to query XML, YAML and Avro with SQL
The awkward formats. How nested elements flatten into dot-path columns, with worked examples for each and the honest limits.
Privacy, security and compliance
How to query a CSV without uploading it anywhere
What client-side querying means in practice, and three ways to verify for yourself that nothing leaves your machine. Start here if you are evaluating.
Private SQL analytics for regulated data
What a third-party upload triggers under GDPR, HIPAA and PCI — and the six questions your compliance team will ask, with answers.
Working with client data under an NDA
For consultants and auditors: which clauses an online tool quietly breaches, a workflow you can defend, and what to tell a client who asks.
What is client-side data virtualization?
The term, explained without jargon — querying data where it already lives — plus how it compares to a warehouse, and when it is the wrong tool.
Working offline
Using SQL offline and on air-gapped machines
Disconnect entirely and keep working. How to keep a local copy, how to move it to an air-gapped machine, and the one feature that degrades.
Also worth reading
- How To Use — the complete reference: file options, SQL syntax, exports
- Licensing & Contact — internal deployment, written licences, security review packs
Everything in these guides runs in your browser. Nothing is uploaded.
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