Oracle 1Z0-051 問題集

質問 1：
Which three statements are true regarding sub queries? (Choose three.)
A. Sub queries can contain GROUP BY and ORDER BY clauses
B. Main query and sub query can get data from different tables
C. Main query and sub query must get data from the same tables
D. Only one column or expression can be compared between the main query and subqeury
E. Multiple columns or expressions can be compared between the main query and sub query
F. Sub queries can contain ORDER BY but not the GROUP BY clause
正解：A,B,E

質問 2：
You created an ORDERS table with the following description:
Exhibit:

You inserted some rows in the table. After some time, you want to alter the table by creating the PRIMARY KEY constraint on the ORD_ID column.
Which statement is true in this scenario?
A. The primary key constraint can be created only a the time of table creation
B. You cannot add a primary key constraint if data exists in the column
C. You cannot have two constraints on one column
D. You can add the primary key constraint even if data exists, provided that there are no duplicate values
正解：D

質問 3：
View the Exhibit and examine the structure of the CUSTOMERS table .Which statement would display the highest credit limit available in each income level in each city in the CUSTOMERS table?

A. SELECT cust_city, cust_income_level, MAX(cust_credit_limit ) FROM customers GROUP BY cust_city, cust_income_level, cust_credit_limit;
B. SELECT cust_city, cust_income_level, MAX(cust_credit_limit) FROM customers GROUP BY cust_city, cust_income_level, MAX(cust_credit_limit);
C. SELECT cust_city, cust_income_level, MAX(cust_credit_limit) FROM customers GROUP BY cust_credit_limit, cust_income_level, cust_city ;
D. SELECT cust_city, cust_income_level, MAX(cust_credit_limit) FROM customers GROUP BY cust_city, cust_income_level;
正解：D

質問 4：
Which is an iSQL*Plus command?
A. DESCRIBE
B. RENAME
C. UPDATE
D. DELETE
E. SELECT
F. INSERT
正解：A
解説: (Topexam メンバーにのみ表示されます)

質問 5：
Which two statements are true regarding constraints? (Choose two.)
A. A constraint is enforced only for the INSERT operation on a table.
B. All constraints can be defined at the column level as well as the table level.
C. A column with the UNIQUE constraint can contain NULL values.
D. A constraint can be disabled even if the constraint column contains data.
E. A foreign key cannot contain NULL values.
正解：C,D
解説: (Topexam メンバーにのみ表示されます)

質問 6：
Examine the data in the CUSTOMERS table:

You want to list all cities that have more than one customer along with the customer details.
Evaluate the following query:
SQL>SELECT c1.custname, c1.city
FROM Customers c1 __________________ Customers c2
ON (c1.city=c2.city AND c1.custname<>c2.custname);
Which two JOIN options can be used in the blank in the above query to give the correct output? (Choose two.)
A. LEFT OUTER JOIN
B. FULL OUTER JOIN
C. JOIN
D. RIGHT OUTER JOIN
E. NATURAL JOIN
正解：C,D

質問 7：
The STUDENT_GRADES table has these columns:
STUDENT_ID NUMBER(12)
SEMESTER_END DATE
GPA NUMBER(4,3)
Which statement finds the highest grade point average (GPA) per semester?
A. SELECT (gpa) FROM student_grades GROUP BY semester_end WHERE gpa IS NOT NULL;
B. SELECT MAX(gpa) GROUP BY semester_end WHERE gpa IS NOT NULL FROM student_grades;
C. SELECT MAX(gpa) FROM student_grades WHERE gpa IS NOT NULL;
D. SELECT MAX(gpa) FROM student_grades WHERE gpa IS NOT NULL GROUP BY semester_end;
E. SELECT MAX(gpa) FROM student_grades GROUP BY semester_end WHERE gpa IS NOT NULL;
正解：D
解説: (Topexam メンバーにのみ表示されます)