Using the Query Playground
Validation tells you whether two tables match. The playground is for the question validation cannot answer: whether the data is right. It runs read-only statements against the source or the target of a project, which makes it the fastest way to compare a specific row on both sides.
Before you start
- A project with at least one connection tested.
- A specific question — the row cap makes this a spot-check tool, not an export tool.
Steps
- 1
Navigate to 'Query Playground' from the sidebar
- 2
Select a project and choose source or target database
- 3
Write a read-only SQL query (SELECT, SHOW, DESCRIBE, EXPLAIN)
- 4
Press Ctrl+Enter or click 'Run Query' to execute
- 5
Results are displayed in a table format, capped at 500 rows
- 6
Use this to verify data integrity after migration
What goes wrong
Read-only is enforced, not advisory
Writes are rejected rather than executed. That is deliberate: the playground points at production databases, and an UPDATE typed into the wrong tab is not a recoverable mistake.
The 500-row cap is on the result, not the scan
A query that scans a large table still does the work on your database. Add a WHERE clause rather than relying on the cap to make an expensive query cheap.
Check the ends, not the beginning
ORDER BY on a primary key and inspecting the first rows tells you the load started correctly. The interesting failures — truncation, encoding, timezone — live in the maximum values and the non-ASCII rows.