SQL UPDATE is the command used to update existing table rows with new data values. SQL ALTER table command is used to modify the definition (structure) of a table by modifying the definition of its column.

Which command is used to modify existing rows in SQL?

The SQL UPDATE Query is used to modify the existing records in a table. You can use the WHERE clause with the UPDATE query to update the selected rows, otherwise all the rows would be affected.

Which of the following command is used to modify an existing table?

The alter command is used to modify an existing database, table, view or other database objects that might need to change during the life cycle of a database.