单项选择题
Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables:
EMPLOYEES
EMPLOYEE_ID NUMBER Primary Key
FIRST_NAME VARCHAR2 (25)
LAST_NAME VARCHAR2 (25)
HIRE_DATE DATE
NEW EMPLOYEES
EMPLOYEE_ID NUMBER Primary Key
NAME VARCHAR2 (60)
Which DELETE statement is valid?（）
A. DELETE FROM employees WHERE employee_id = (SELECT employee_id FROM employees);
B. DELETE * FROM employees WHERE employee_id = (SELECT employee_id FROM new_ employees);
C. DELETE FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE name = ('Carrey')'
D. DELETE * FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE last_ name = ('Carrey')'
相关考题
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单项选择题
Examine the structure of the STUDENTS table: You need to create a report of the 10 students who achieved the highest ranking in the course INT SQL and who completed the course in the year 1999.Which SQL statement accomplishes this task?（）
A.
B.
C.
D.
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单项选择题
The CUSTOMERS table has these columns: CUSTOMER_ID NUMBER (4) NOT NULL CUSTOMER_NAME VARCHAR2 (100) NOT NULL STREET_ADDRESS VARCHAR2 (150) CITY_ADDRESS VARHCAR2 (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. You need to determine how dispersed your customer base is. Which expression finds the number of different countries represented in the CUSTOMERS table?（）
A. COUNT(UPPER(country_address))
B. COUNT(DIFF(UPPER(country_address)))
C. COUNT(UNIQUE(UPPER(country_address)))
D. COUNT DISTINTC UPPER(country_address)
E. COUNT(DISTINTC (UPPER(country_address))) -
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 WHERE department_id IN (10,20);
E. CREATE FORCE VIEW emp_vu AS SELECT * FROM employees WHERE department_id IN (10,20) NO UPDATE;
