Final answer:
The syntax provided in the question for creating a view is incorrect because it lacks a FROM clause and a correctly placed GROUP BY clause. A valid syntax for creating a view includes SELECT, FROM, SUM, and GROUP BY clauses to define how data is aggregated and grouped.
Step-by-step explanation:
The question addresses the action of creating a view in a relational database management system using SQL (Structured Query Language). When creating a view, especially to view a subset of a table, it is crucial that the correct syntax is followed to ensure the view is created properly and the desired data is displayed. However, the syntax provided in the option (D) is incorrect. The correct syntax requires a FROM clause to indicate the table from which the data is to be selected and a GROUP BY clause correctly placed after specifying the selection criteria. Here is an example of the valid syntax:
CREATE VIEW album_cost AS
SELECT album_id, SUM(unit_price) AS total_cost FROM album GROUP BY album_id;
In this example, we are defining a new view named 'album_cost' that will display the sum of 'unit_price' for each unique 'album_id' from the 'album' table. The 'AS total_cost' portion of the SQL statement assigns an alias to the result of the SUM aggregation function, which represents the total cost of each album. It's essential to ensure that all aggregated columns in a SELECT statement that are not within aggregate functions themselves must be included in the GROUP BY clause. Otherwise, the SQL engine will not understand how exactly to group the data, resulting in an error.