Which SQL command would you use to update existing data in a database?

The SQL command used to modify or update existing data within a database is the UPDATE command. This command allows users to change the values of one or more columns in one or more records of a table. When utilizing the UPDATE statement, you typically specify the table that contains the data you want to adjust, the new values you wish to set, and usually a WHERE clause that identifies which records should be updated.

For example, if you wanted to change a customer's address in a customer table, you would use the UPDATE command to set the new address for the specific customer row identified by their unique identifier. This approach ensures that only the intended records are altered, preventing unintentional changes to the entire dataset.

Other commands such as INSERT, SELECT, and DELETE serve different functions; INSERT is used for adding new records, SELECT retrieves data without altering it, and DELETE removes records, none of which address the task of updating existing data. Thus, the UPDATE command is the appropriate choice for modifying existing entries in a database.