SQL diff checker

What is a SQL diff?

A SQL diff compares two versions of a SQL query or schema and highlights exactly what was added, removed, or changed. The concept is the same as git diff but applied specifically to SQL code, making it easy to scan changes without reading both versions end to end.

This is especially useful when queries are long or structurally complex. A diff lets you focus on the meaningful changes — a new join condition, an updated filter, a renamed alias — without getting lost in the parts that stayed the same.

When to use a SQL diff tool

• Reviewing query changes in pull requests before merging
• Auditing database migration files — comparing the old and new versions of a CREATE TABLE, view, or stored procedure
• Debugging regressions — pasting the last working version of a query alongside the current broken one to spot the change
• Documenting how a query or schema evolved over time
• Verifying that an auto-formatter or refactor didn't change query logic

How the diff is computed

The tool uses a standard line-by-line diffing algorithm. Lines present only in the original are marked as removed (red), lines present only in the modified version are marked as added (green), and matching lines appear unchanged. Both sides include line numbers so you can reference specific changes easily.

Stop writing SQL manually for dashboards

If you find yourself iterating on SQL queries to build reports and charts, Basedash can eliminate that loop entirely. Describe the metric or visualization you need in plain English, and Basedash generates the SQL, runs it against your database, and renders the result — no manual query writing or diffing needed. It connects to PostgreSQL, MySQL, BigQuery, Snowflake, and 750+ other data sources.