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';
相关考题
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单项选择题
Which is an iSQL*Plus command? （）
A. INSERT
B. UPDATE
C. SELECT
D. DESCRIBE
E. DELETE
F. RENAME -
单项选择题
Which SQL statement would you use to remove a view called EMP_DEPT_VU from your schema?（）
A. DROP emp_dept_uv;
B. DELETE emp_dept_uv;
C. REMOVE emp_dept_uv;
D. DROP VIEW emp_dept_uv;
E. DELETE VIEW emp_dept_uv;
F. REMOVE VIEW emp_dept_uv; -
多项选择题
Which four are valid Oracle constraint types? （）
A. CASCADE
B. UNIQUE
C. NONUNIQUE
D. CHECK
E. PRIMARY KEY
F. CONSTANT
G. NOT NULL
