How to formulate an SQL query to update existing data in a table?

The UPDATE operator is used to modify existing data in a SQL table. Its basic syntax looks like this:

UPDATE table_name
SET column_name1 = new_value1, column_name2 = new_value2
WHERE condition;

It is important to always specify the WHERE condition to update only the desired records. If the condition is not specified, all rows in the table will be updated.

Example:

UPDATE users
SET email = 'newemail@example.com'
WHERE id = 5;

This query updates the email field for the user with id equal to 5.