Which three statements about subquerie...

多项选择题Which three statements about subqueries are true?（）

A. A single row subquery can retrieve only one column and one row.
B. A single row subquery can retrieve only one row but many columns.
C. A multiple row subquery can retrieve multiple rows and multiple columns.
D. A multiple row subquery can be compared by using the ">" operator.
E. A single row subquery can use the IN operator.
F. A multiple row subquery can use the "=" operator.

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1.单项选择题In a SELECT statement that includes a WHERE clause, where is the GROUP BY clause placed in the SELECT statement?（）

A. Immediately after the SELECT clause
B. Before the WHERE clause
C. Before the FROM clause
D. After the ORDER BY clause
E. After the WHERE clause

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2.单项选择题 Examine the data of the EMPLOYEES table.
EMPLOYEES (EMPLOYEE_ID is the primary key. MGR_ID is the ID of managers and refers to the EMPLOYEE_ID)

Which statement lists the ID, name, and salary of the employee, and the ID and name of the employee's manager, for all the employees who have a manager and earn more than 4000?（）

A.
B.
C.
D.
E.

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3.多项选择题When should you create a role? （）

A.To simplify the process of creating new users using the CREATE USER xxx IDENTIFIED by yyy statement.
B.To grant a group of related privileges to a user.
C.When the number of people using the database is very high.
D.To simplify the process of granting and revoking privileges.
E.To simplify profile maintenance for a user who is constantly traveling.

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4.单项选择题Which clause would you use in a SELECT statement to limit the display to those employees whose salary is greater then 5000?（）

A. ORDER BY SALARY > 5000
B. GROUP BY SALARY > 5000
C. HAVING SALARY > 5000
D. WHERE SALARY > 5000

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5.单项选择题 Examine the structure of the EMPLOYEES table:
EMPLOYEE_ID NUMBER Primary Key
FIRST_NAME VARCHAR2(25)
LAST_NAME VARCHAR2(25)
DEPARTMENT_ID NUMBER
SALARY NUMBER
What is the correct syntax for an inline view?（）

A. SELECT a.last_name, a.salary, a.department_id,
B. maxsal FROM employees a, (SELECT department_id, max(salary)maxsal FROM employees GROUP BY department_id) b WHERE a.department_id = b.department_id AND a.salary < b.maxsal;
C. SELECT a.last name, a.salary, a.department_id FROM employees a WHERE a.department_id IN (SELECT department_id FROM employees b GROUP BY department_id having salary = (SELECT max(salary) from employees))
D. SELECT a.last_name, a.salary, a.department_id FROM employees a WHERE a.salary = (SELECT max(salary) FROM employees b WHERE a.department _ id = b.department _ id);
E. SELECT a.last_name, a.salary, a.department_id FROM employees a WHERE (a.department_id, a.salary) IN (SELECT department_id, a.salary) IN (SELECT department_id max(salary) FROM employees b GROUP BY department_id ORDER BY department _ id);

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6.单项选择题Which SQL statement generates the alias Annual Salary for the calculated column SALARY*12?（）

A. SELECT ename, salary*12 'Annual Salary' FROM employees;
B. SELECT ename, salary*12 "Annual Salary" FROM employees;
C. SELECT ename, salary*12 AS Annual Salary FROM employees;
D. SELECT ename, salary*12 AS INITCAP("ANNUAL SALARY") FROM employees

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7.单项选择题In which scenario would index be most useful?（）

A. The indexed column is declared as NOT NULL.
B. The indexed columns are used in the FROM clause.
C. The indexed columns are part of an expression.
D. The indexed column contains a wide range of values.

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8.多项选择题Which two are true about aggregate functions?（）

A. You can use aggregate functions in any clause of a SELECT statement.
B. You can use aggregate functions only in the column list of the SELECT clause and in the WHERE clause of a SELECT statement.
C. You can mix single row columns with aggregate functions in the column list of a SELECT statement by grouping on the single row columns.
D. You can pass column names, expressions, constants, or functions as parameters to an aggregate function.
E. You can use aggregate functions on a table, only by grouping the whole table as one single group.
F. You cannot group the rows of a table by more than one column while using aggregate functions.

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9.多项选择题Which two are attributes of iSQL*Plus? （）

A./SQL*Plus commands cannot be abbreviated.
B./SQL*Plus commands are accessed from a browser.
C./SQL*Plus commands are used to manipulate data in tables.
D./SQL*Plus commands manipulate table definitions in the database.
E./SQL*Plus is the Oracle proprietary interface for executing SQL statements.

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10.单项选择题 Examine the structure if the EMPLOYEES and NEW EMPLOYEES tables:

Which MERGE statement is valid?（）

A.
B.
C.
D.

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