Which of the following SQL commands is used to modify existing data in a…

Concept

A data-manipulation command changes the contents of rows, whereas a data-definition command changes the structure of a table.

In SQL, UPDATE is the statement for assigning new values to columns of existing rows. Its core form is UPDATE table_name SET column_name = value, with an optional WHERE condition.

Application

Apply the command definition to this item:

1. Identify the target operation: values in rows already stored in a table must change.

2. Choose the SQL data-manipulation statement designed for that operation: UPDATE.

3. Use SET to specify the new column value and WHERE to limit the affected rows, for example: UPDATE employees SET salary = 50000 WHERE id = 7.

Contrast

• MODIFY is a general verb and also appears in some vendor-specific schema-alteration syntax; it is not the data-manipulation statement required here.

• CHANGE is an everyday synonym and a vendor-specific column-definition keyword in some systems; it does not name the required standard data-change statement.

• NEW describes a prospective value or row image in some database contexts; it does not perform the operation.

• UPDATE is the SQL data-manipulation statement that assigns new values to columns of existing rows.

Cross-check

The PostgreSQL command reference defines UPDATE as changing specified column values in rows that satisfy a condition, which matches the operation in the stem.

Result

Therefore, the required command is UPDATE.