SQL Command for Modifying Existing Records

The correct answer is 'B. update'.

The 'update' command in SQL is specifically used to modify existing records within a table. Here's how it works:

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;

Explanation:

• UPDATE table_name: Specifies the table you want to modify.
• SET column1 = value1, column2 = value2, ...: Sets new values for specific columns in the record(s) you want to change.
• WHERE condition: Optionally filters which records are updated. This ensures you only modify the intended records.

Example:

UPDATE Customers
SET FirstName = 'John', LastName = 'Doe'
WHERE CustomerID = 1;

This example updates the 'FirstName' and 'LastName' columns in the 'Customers' table for the record where 'CustomerID' is 1.

Why other options are incorrect:

• 'select' retrieves data from a table, but doesn't modify it.
• 'insert' adds new records to a table.
• 'None of them' is incorrect as 'update' is the correct command.