sql语句-平均工资-员工工资

表创建：

    员工表：

    DROP TABLE IF EXISTS `employee`;
    CREATE TABLE `employee` (
          `emp_id` int(11) NOT NULL AUTO_INCREMENT,
          `dept_id` int(11) DEFAULT NULL,
          `emp_wage` int(11) DEFAULT NULL,
          PRIMARY KEY (`emp_id`)

    ) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

    员工表数据：

      insert  into `employee`(`emp_id`,`dept_id`,`emp_wage`) values (1,1,10000),(2,2,20000),(3,4,5000),(4,4,3000),(5,3,7500);

    部门表：

        DROP TABLE IF EXISTS `department`;
        CREATE TABLE `department` (
              `dept_id` int(11) NOT NULL AUTO_INCREMENT,
              `dept_name` varchar(50) COLLATE utf8_unicode_ci DEFAULT NULL,
              PRIMARY KEY (`dept_id`)

        ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

    部门表数据：

    insert  into `department`(`dept_id`,`dept_name`) values (1,'信息部'),(2,'技术部'),(3,'外交部'),(4,'人事');

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1) 求各部门的平均工资

select dept_name '部门名称',avg(emp_wage) "平均工资" from employee  e left join department d on e.dept_id = d.dept_id  GROUP BY emp_wage
 
2) 列出工资大于5000的员工所属部门名称、员工id和员工工资


select d.dept_name '部门名称',e.emp_id '员工id',
e.emp_wage'员工工资' from employee  e left join  department d on 
e.dept_id=d.dept_id where e.emp_wage>5000
group by d.dept_name,e.dept_id ,e.emp_id,e.emp_wage