Question

我有两个表＆＃34;员工表，从属表＆＃34;

员工表有＆＃34; ID，employee_id，employee_name＆＃34;

依赖表具有＆＃34; ID，employee_id，dependent_name，relationship＆＃34;

，员工表的值为("1, 123, Vincent")

和依赖表的值是

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

我将如何显示employee_id和employee_name及其受抚养人数？

喜欢选择employee_id，employee_name，count（dependent）作为dependents ???

Answer 1

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

Answer 2

尝试此查询：

 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

Answer 3

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

Answer 4

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

Answer 5

试试这个有效的

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

select employee_name，count（dependent）作为员工错误的依赖项

5 个答案: