Databricks Time Travel : How to Compare With Previous Versions

In Databricks with Delta Lake, you can retrieve and compare the old and new versions of a table after an UPDATE operation using time travel or Delta Lake history.

Step 1: Create a Table

CREATE OR REPLACE TABLE default.emp_1 (
    id INT,
    name STRING,
    salary INT
) USING DELTA;

INSERT INTO default.emp_1 VALUES 
(1, 'Alice', 50000),
(2, 'Bob', 60000),
(3, 'Charlie', 70000);

Step 2: Update the Table

UPDATE default.emp_1 
SET salary = salary + 5000 
WHERE id = 2;

Step 3: Describe History

Query

DESCRIBE HISTORY default.emp_1;

Output

Step 4: Compare Versions

SELECT old.id, old.name, old.salary AS old_salary, new.salary AS new_salary
FROM default.emp_1 VERSION AS OF 0 old
JOIN default.emp_1 new ON old.id = new.id
WHERE old.salary <> new.salary;

🚀 Key Takeaways

✅ You use VERSION AS OF
✅ DESCRIBE HISTORY table_name Shows all past versions.
✅ You can time travel to see old data without renaming tables.