Which SQL command would you use to change existing data in a table?

The command used to change existing data in a table is the UPDATE command. This command allows you to modify the records within a specific table by setting new values for one or more columns based on specified conditions.

For example, if you have a Customers table and you want to change the Email address for a specific customer, you would use the UPDATE statement to set the new email address where the conditions match the particular customer's ID or another unique identifier. The syntax typically looks like this:

UPDATE Customers

SET Email = 'newemail@example.com'

WHERE CustomerID = 1;

This command effectively locates the records that meet the criteria defined in the WHERE clause and updates the specified columns with the new values. Other commands like ALTER are used for changing the structure of the table itself, while MODIFY is not a recognized SQL command for updating data in standard SQL. PUSH is not relevant in this context as it does not pertain to SQL operations for modifying data. Thus, UPDATE is specifically designed for modifying existing data, which is why it is the correct choice.