单项选择题
In which case would you use a FULL OUTER JOIN?（）
A. Both tables have NULL values.
B. You want all unmatched data from one table.
C. You want all matched data from both tables.
D. You want all unmatched data from both tables.
E. One of the tables has more data than the other.
F. You want all matched and unmatched data from only one table.
相关考题
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多项选择题
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) Which three statements inserts a row into the table? （）
A. INSERT INTO employees VALUES (NULL, 'JOHN','Smith');
B. INSERT INTO employees( first_name, last_name) VALUES ('JOHN','Smith');
C. INSERT INTO employees VALUES ('1000','JOHN','NULL');
D. INSERT INTO employees(first_name,last_name, employee_id) VALUES ('1000, 'john','Smith');
E. INSERT INTO employees (employee_id) VALUES (1000);
F. INSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, 'john',"); -
单项选择题
Evaluate the SQL statement: SELECT LPAD (salary,10,*) FROM EMP WHERE EMP _ ID = 1001; If the employee with the EMP_ID 1001 has a salary of 17000, what is displayed?（）
A. 17000.00
B. 17000*****
C. ****170.00
D. **17000.00
E. an error statement -
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 name = 'carrey');
