测试题

#1.  下面的语句是否可以执行(可以)

SELECT last_name,job_id,salary AS sal FROM employees;

#2.下面的语句是否可以执行（可以）SELECT * FROM employees;

#3.找出下面语句的错误(错用中文逗号)

SELECT employee_id,last_name, salary * 12  AS "ANNUAL  SALARY" FROM employees;

#4.显示表departments的结构，并查询其中的全部数据

DESC departments;

SELECT * FROM departments;

#5.显示出表employees中的全部job_id(不能重复)

SELECT DISTINCT job_id FROM employees;

#6.显示出表employees的全部列，各个列之间用逗号连接，列头显示成out_put

SELECT IFNULL(commission_pct,0) AS 奖金率, commission_pct FROM employees;

SELECT CONCAT(first_name,',',email,',',phone_number,',',job_id,',',IFNULL(commission_pct,0)) AS out_put  FROM  employees;