在各种物件的翻转过程中,应正确估计被翻转物件的质量及重心位置,正确()物件的系挂吊点,是确保物件翻转工艺过程安全而顺利完成的关键。
查看答案
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'
以下选项不属于市场营销环境特点的是()。
A. 单一性
B. 复杂性
C. 动态性
D. 多变性