单项选择题
Examine the data in the EMPLOYEES table.
On the EMPLOYEES table, EMPLOYEE_ID is the primary key. MGR_ID is the ID of managers and refers to the EMPLOYEE_ID. The JOB_ID column is a NOT NULL column.
Evaluate this DELETE statement:
Why does the DELETE statement fail when you execute it?（）
A. There is no row with dept_id 90 in the EMPLOYEES table.
B. You cannot delete the JOB_ID column because it is a NOT NULL column.
C. You cannot specify column names in the DELETE clause of the DELETE statement.
D. You cannot delete the EMPLOYEE_ID column because it is the primary key of the table.
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单项选择题
Which substitution variable would you use if you want to reuse the variable without prompting the user each time?（）
A.&
B.ACCEPT
C.PROMPT
D.&& -
单项选择题
What is true about the WITH GRANT OPTION clause?（）
A.It allows a grantee DBA privileges.
B.It is required syntax for object privileges.
C.It allows privileges on specified columns of tables.
D.It is used to grant an object privilege on a foreign key column.
E.It allows the grantee to grant object privileges to other users and roles. -
单项选择题
The EMP table has these columns: Management wants a list of names of employees who have been with the company for more than five years. Which SQL statement displays the required results?（）
A. SELECT ENAME FROM EMP WHERE SYSDATE-HIRE_DATE > 5;
B. SELECT ENAME FROM EMP WHERE HIRE_DATE-SYSDATE > 5;
C. SELECT ENAME FROM EMP WHERE (SYSDATE-HIRE_DATE)/365 > 5;
D. SELECT ENAME FROM EMP WHERE (SYSDATE-HIRE_DATE)* 365 > 5;
