CSV Look
Drop a CSV to get a table, ask it with SQL, and save the answer. Your file never leaves this browser.
On 24 test samples (including legacy-encoded Excel exports, Unicode Text, 1,234-style numbers and blank cells) all 24 were read with every cell and every answer right. The common read-as-UTF-8 path got 10.
Wrap column names that contain spaces in double quotes, e.g. SELECT region, SUM("sales amount") FROM sales GROUP BY region
Out of scope — Excel files (xlsx), files over 200MB and writing changes back to the file. Only cells written like 1,234 or -1,200.50 are read as numbers; IDs with a leading zero (postcodes, phone numbers) and numbers longer than 15 digits stay text. In saved CSV and copied tables, text cells starting with = + - @ get a leading ' so spreadsheets do not run them as formulas.
The engine (SQLite, about 0.3MB) is fetched from this site when you add your first file. Your files, tables and results are not stored anywhere and are gone when you close the tab.