m0_49089924的博客

1.查询各部门中工资比本部门平均工资高的员工的员工号,姓名和工资 ①查询各部门的平均工资 SELECT AVG(salary),department_id FROM employees GROUP BY department_id; ②连接①结果集和employees表,进行筛选 SELECT employee_id,last_name,salary,e.department_id FROM employees e INNER JOIN ( SELECT AVG(salary) ag ,depart

1.定义变量语句 数据类型 变量名 = 变量值; 使用变量语句 变量名 (=) (变量值);不再加数据类型. class BitTest{ public static void main(String[] args){ //练习 int num1 = 10; int num2 = 20;//目的:变量的值交换 //方式一:空杯子法.定义临时变量. //推荐的方式 int temp = num1; num1 = num2; num2 = temp; System.out.println(num1);