Which two tasks can your perform by using the TO_CHAR function? （）

多项选择题The CUSTOMERS table has these columns: CUSTOMER_ID NUMBER(4) NOT NULL CUSTOMER_NAME VARCHAR2(100) NOT NULL STREET_ADDRESS VARCHAR2(150) CITY_ADDRESS VARCHAR2(50) STATE_ADDRESS VARCHAR2(50) PROVINCE_ADDRESS VARCHAR2(50) COUNTRY_ADDRESS VARCHAR2(50) POSTAL_CODE VARCHAR2(12) CUSTOMER_PHONE VARCHAR2(20) The CUSTOMER_ID column is the primary key for the table. Which two statements find the number of customers? （）

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

多项选择题Which four statements correctly describe functions that are available in SQL? （）

A. INSTR returns the numeric position of a named character.
B. NVL2 returns the first non-null expression in the expression list.
C. TRUNCATE rounds the column, expression, or value to n decimal places.
D. DECODE translates an expression after comparing it to each search value.
E. TRIM trims the heading of trailing characters (or both) from a character string.
F. NVL compares two expressions and returns null if they are equal, or the first expression of they are not equal.
G. NULLIF compares twp expressions and returns null if they are equal, or the first expression if they are not equal.

单项选择题You need to create a view EMP_VU. The view should allow the users to manipulate the records of only the employees that are working for departments 10 or 20. Which SQL statement would you use to create the view EMP_VU? （）

A. CREATE VIEW emp_vu AS SELECT * FROM employees WHERE department _ id IN (10,20);
B. CREATE VIEW emp_vu AS SELECT * FROM employees WHERE department_id IN (10,20) WITH READ ONLY;
C. CREATE VIEW emp_vu AS SELECT * FROM employees WHERE department_id IN (10,20) WITH CHECK OPTION;
D. CREATE FORCE VIEW emp_vu AS SELECT * FROM employees WITH department_id IN (10,20);
E. CREATE FORCE VIEW emp_vu AS SELECT * FROM employees WHERE department_id IN (10,20) NO UPDATE;

多项选择题From SQL*Plus, you issue this SELECT statement: SELECT* FROM order; You use this statement to retrieve data from a data table for （）.

A. Updating
B. Viewing
C. Deleting
D. Inserting
E. Truncating

单项选择题Evaluate this SQL statement: SELECT e.employee_id, (.15* e.salary) + (.5 * e.commission_pct) + (s.sales amount * (.35 * e.bonus)) AS CALC_VALUE FROM employees e, sales s WHERE e.employee_id = s.emp_id; What will happen if you remove all the parentheses from the calculation? （）

A. The value displayed in the CALC_VALUE column will be lower.
B. The value displayed in the CALC_VALUE column will be higher.
C. There will be no difference in the value displayed in the CALC_VALUE column.
D. An error will be reported.