How to Change Passwords in BigQuery

Galaxy Glossary

How do I safely change a stored user password in BigQuery?

Update a user’s stored password (usually the hashed value) in a BigQuery table with one safe, atomic UPDATE statement.

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Description

Example H2

Example H3

How do I update a user’s password in BigQuery?

Use an UPDATE statement that targets the specific row and writes a new hashed password into the password column. Always hash on the client or in-query to avoid storing plain text.

Which hashing functions can I call directly in BigQuery?

BigQuery Standard SQL offers SHA256, SHA512, MD5 and FARM_FINGERPRINT. SHA256 is the most common choice for password hashes when combined with a per-user salt.

Syntax recap

UPDATE `project.dataset.table` SET column=expression WHERE condition;

Can I rotate many passwords at once?

Yes. Wrap the UPDATE in a transaction (via multi-statement script) or restrict by WHERE IN to batch multiple user IDs.

How do I verify the update succeeded?

Immediately SELECT the row after the UPDATE inside the same script or query window. BigQuery’s snapshot isolation guarantees you see the new hash.

Best practice: always salt + hash

Store a unique salt per user (e.g., a UUID). Concatenate the salt with the clear-text password, hash, then store both salt and password_hash columns.

Recommended column schema

password_hash STRING, salt STRING, last_changed TIMESTAMP

How to run the change inside an application?

Prepare the UPDATE statement as a parameterised query in your language SDK (Python, Java, Go). Pass the new salt and hash as parameters to avoid SQL injection.

When should I avoid changing passwords in BigQuery?

Never change Google Cloud user credentials here—BigQuery manages auth via IAM. Only update passwords your application stores in tables such as Customers.

Wrap-up

One precise UPDATE with hashing, salting, and a WHERE clause is all you need to change a stored password safely in BigQuery.

Why How to Change Passwords in BigQuery is important

How to Change Passwords in BigQuery Example Usage


DECLARE new_pass   STRING DEFAULT 'SuperS3cret!';
DECLARE new_salt   STRING DEFAULT GENERATE_UUID();
DECLARE cust_id    INT64  DEFAULT 42;

UPDATE `shop.sales.Customers`
SET    password_hash = TO_HEX(SHA256(CONCAT(new_salt, new_pass))),
       salt          = new_salt,
       last_changed  = CURRENT_TIMESTAMP()
WHERE  id = cust_id;

SELECT id, email, last_changed
FROM   `shop.sales.Customers`
WHERE  id = cust_id;

How to Change Passwords in BigQuery Syntax


UPDATE `project_id.dataset_id.Customers`
SET    password_hash = TO_HEX(SHA256(CONCAT(@salt, @new_password))),
       salt          = @salt,
       last_changed  = CURRENT_TIMESTAMP()
WHERE  id = @customer_id;

Common Mistakes

Updating the password without a WHERE clause. This overwrites every row. Always target a single user (id = ?) or a controlled list.
Storing clear-text passwords. Always hash (prefer SHA256) and salt before writing. BigQuery supports hashing functions directly.