Question

Which of the following SQL statements is not valid?

A. SELECT isbn
FROM books
MINUS
SELECT isbn
FROM orderitems;
B. SELECT isbn, name
FROM books, publisher
WHERE books.pubid(+) = publisher.pubid(+);
C. SELECT title, name
FROM books NATURAL JOIN publisher
D. All of the above SQL statements are valid.

Answer 1

The not valid SQL statement among the provided options is Option B, which uses non-standard syntax for outer joins, specific to Oracle's SQL and not part of standard SQL.

Step-by-step explanation:

The student's question pertains to the validity of SQL statements. Among the options provided:

• Option A is a valid SQL statement using a MINUS operator to subtract the result set of one SELECT statement from another.
• Option B features an outer join syntax that's not standard SQL. The use of the (+) operator for joins is specific to Oracle's SQL syntax and is not standard SQL.
• Option C uses a NATURAL JOIN, which is a valid SQL statement that joins tables based on all columns with the same names.

Thus, the not valid SQL statement from the options provided is Option B, as it uses non-standard SQL syntax for joins.