如何查询黑龙江的人力资源网站和西安的房价信息？

黑龙江建设人力资源网站,西安房价,wordpress后台定制,营销方式和营销策略2023.9.4 MySQL 分组查询的学习笔记如下#xff1a; #分组查询 /* 分组查询中的筛选条件分为两类#xff1a;数据源 位置 关键字 分组前筛选 原始表 group by前面 where 分组后筛选 分组后的结果集 group by后面 having */ #查询每…2023.9.4 MySQL 分组查询的学习笔记如下 #分组查询 /* 分组查询中的筛选条件分为两类数据源 位置 关键字 分组前筛选 原始表 group by前面 where 分组后筛选 分组后的结果集 group by后面 having */ #查询每个工种的最高工资 SELECT MAX(salary),job_id FROM employees GROUP BY job_id; #查询每个位置上的部门个数 SELECT COUNT(*),location_id FROM departments GROUP BY location_id; #查询邮箱中包含a字符的每个部门的平均工资。 SELECT AVG(salary),department_id FROM employees WHERE email LIKE %a% GROUP BY department_id; #查询有奖金的每个领导手下员工的最高工资 SELECT MAX(salary),manager_id FROM employees WHERE commission_pct IS NOT NULL GROUP BY manager_id; #查询哪个部门的员工个数2 SELECT COUNT(*),department_id FROM employees GROUP BY department_id HAVING COUNT(*)2; #查询每个工种有奖金的员工的最高工资 SELECT MAX(salary),job_id FROM employees WHERE commission_pct IS NOT NULL GROUP BY job_id; #根据上述结果继续筛选最高工资12000的结果。 SELECT MAX(salary),job_id FROM employees WHERE commission_pct IS NOT NULL GROUP BY job_id HAVING MAX(salary)12000; #查询领导编号102的每个领导手下的最低工资5000的领导编号是哪个以及其最低工资。 SELECT manager_id,MIN(salary) FROM employees WHERE manager_id102 GROUP BY manager_id HAVING MIN(salary)5000; #按员工姓名的长度分组查询每一组的员工个数筛选员工个数5的有哪些。 SELECT LENGTH(last_name),COUNT(*) FROM employees GROUP BY LENGTH(last_name) HAVING COUNT(*)5; #查询每个部门每个工种的员工的平均工资,并按平均工资的高低显示。 SELECT department_id,job_id,AVG(salary) FROM employees GROUP BY department_id,job_id ORDER BY AVG(salary) DESC; 课后习题 #1、查询各job_id的员工工资的最大值最小值平均值总和。并按job_id升序 SELECT job_id,MAX(salary),MIN(salary),AVG(salary),SUM(salary) FROM employees GROUP BY job_id ORDER BY job_id ASC; #2、查询员工最高工资和最低工资的差距 SELECT MAX(salary)-MIN(salary) FROM employees; #3、查询各个管理者手下员工的最低工资其中最低工资不能低于6000没有管理者的员工不计算在内。 SELECT manager_id,MIN(salary) FROM employees WHERE manager_id IS NOT NULL GROUP BY manager_id HAVING MIN(salary)6000; #4、查询所有部门的编号员工数量和工资平均值并按平均工资降序。