Which is the correct syntax to modify an existing table by adding a new column?

• A. ALTER TABLE table_name ADD COLUMN column_name datatype
• B. ALTER TABLE ADD COLUMN table_name column_name datatype
• C. UPDATE TABLE table_name ADD COLUMN column_name datatype
• D. MODIFY TABLE table_name ADD COLUMN column_name datatype

Answer: (A)

You modify a table’s structure, not its data, when you add a new column. The correct way is to use ALTER TABLE followed by ADD COLUMN, then specify the new column’s name and its datatype. So the statement is: ALTER TABLE table_name ADD COLUMN column_name datatype. This keeps the table name right after ALTER TABLE and clearly indicates you’re adding a new COLUMN with its type.

The other forms place keywords or the table name in the wrong order or use commands for updating data or altering definitions in ways that don’t add a new column, so they don’t achieve the desired structural change.