多项选择题

Top N analysis requires （） and （）.

A. the use of rowid
B. a GROUP BY clause
C. an ORDER BY clause
D. only an inline view
E. an inline view and an outer query

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多项选择题

The CUSTOMERS table has these columns:

The CUSTOMER_ID column is the primary key for the table.Which two statements find the number of customers? （）

A. SELECT TOTAL(*)   FROM customers;
B. SELECT COUNT(*)   FROM customers;
C. SELECT TOTAL(customer_id)   FROM customers;
D. SELECT COUNT(customer_id)   FROM customers;
E. SELECT COUNT(customers)   FROM customers;
F. SELECT TOTAL(customer_name)   FROM customers;

单项选择题

Examine the description of the EMPLOYEES table:
EMP_ID NUMBER(4) NOT NULL
LAST_NAME VARCHAR2(30) NOT NULL
FIRST_NAME VARCHAR2(30)
DEPT_ID NUMBER(2)
Which statement produces the number of different departments that have employees with last name Smith?（）

A. SELECT COUNT (*) FROM employees WHERE last _name='smith';
B. SELECT COUNT (dept_id) FROM employees WHERE last _name='smith';
C. SELECT DISTINCT (COUNT (dept_id) FROM employees WHERE last _name='smith';
D. SELECT COUNT (DISTINCT dept_id) FROM employees WHERE last _name='smith';
E. SELECT UNIQE (dept_id) FROM employees WHERE last _name='smith';

单项选择题

Which is an iSQL*Plus command?（）

A. INSERT
B. UPDATE
C. SELECT
D. DESCRIBE
E. DELETE
F. RENAME