SQL Data Cleaning Tool — Clean Messy Data in Your Browser

Messy data is the norm. Duplicate rows, inconsistent formats, null values, junk entries. PondPilot lets you clean data with SQL — a more powerful and reproducible approach than manual spreadsheet editing.

Common Cleaning Operations

Remove duplicates:

SELECT DISTINCT ON (email) *
FROM contacts.csv
ORDER BY email, updated_at DESC;

Standardize formats:

SELECT
  TRIM(LOWER(email)) as email,
  UPPER(LEFT(first_name, 1)) || LOWER(SUBSTRING(first_name, 2)) as first_name,
  REPLACE(phone, '-', '') as phone
FROM customers.csv;

Filter out junk:

SELECT * FROM responses.csv
WHERE email IS NOT NULL
  AND email LIKE '%@%.%'
  AND submitted_at IS NOT NULL;

Fix date formats:

SELECT
  *,
  STRPTIME(date_string, '%m/%d/%Y')::DATE as clean_date
FROM events.csv;

Why SQL for Data Cleaning?

Reproducible: Save your cleaning queries. Run them again on the next export. No manual steps to forget.

Readable: A SQL query documents exactly what transformations you applied. Try explaining a spreadsheet’s conditional formatting and manual deletions to a colleague.

Powerful: SQL handles operations that are painful in spreadsheets — deduplication, regex matching, cross-file validation, type casting.

Chain Multiple Cleaning Steps

Real datasets often need several rounds of cleaning. With PondPilot, you can use CTEs (Common Table Expressions) to chain cleaning steps in a single query — first deduplicate, then standardize formats, then filter invalid rows. Each step is explicit and auditable. Save your cleaning query as a template and reuse it every time you receive a new data export, turning a tedious manual process into a repeatable one-click operation.

The Workflow

  1. Drop your messy CSV into PondPilot
  2. Explore the data to understand the mess
  3. Write cleaning queries
  4. Export clean results as CSV

Local and Private

Cleaning often involves raw, unprocessed data — the messiest and most sensitive kind. PondPilot processes it all in your browser. Nothing leaves your machine.

Try It

Open PondPilot and clean your data with SQL.

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