从员工错误中选择employee_name，count（dependent）作为受抚养人答案

【问题标题】：select employee_name, count(dependent) as dependents from employee error从员工错误中选择employee_name，count（dependent）作为受抚养人
【发布时间】：2013-12-09 18:27:00
【问题描述】：

我有这两个表“员工表，依赖表”

员工表有“ID,employee_id,employee_name”

从属表有“ID,employee_id,dependent_name,relationship”

雇员表的值为("1, 123, Vincent")

依赖表的值为

("1, 123, Angel, daughter"),("2, 123, Mary, daughter")

如何显示employee_id 和employee_name 及其家属人数？

like select employee_id, employee_name, count(dependent) as dependent ???

【问题讨论】：

标签： mysql

【解决方案1】：

试试这个查询：

 select e.employee_id,e.employee_name,count(d.employee_id) as dependents
     from department d
     inner join employee e on (e.employee_id=d.employee_id) 
     group by d.employee_id;

Sql Fiddle Example

【讨论】：

【解决方案2】：

使用分组依据和计数

select 
   em.Employee_id, 
   count(*) 
from 
   employee em inner join 
       dependant dp on 
             em.employee_id = dp.employee_id
group by 
       em.employee_id

【讨论】：

【解决方案3】：

试试这个效果

select a.empid ,a.empname , count(b.deptname) from employee a , dependent b 
where a.empid = b.empid and b.empid=123;

【讨论】：

【解决方案4】：

select e.employee_id, e.employee_name , (select count(*) from 
dependent_table where employee_id=e.employee_id) as dependents 
from employee_table as e

【讨论】：

【解决方案5】：

select 
   e.employee_id,
   e.employee_name,
   count(select * from dependent 
         table where 
        dependent table.employee_id=employee table.employee_id) 
from 
      employee table e 
        where e.employee_id=123

试试这个

【讨论】：