Question

我正在尝试执行查询。但它没有像我预期的那样工作。这是我的疑问：

select mo.year,mo.month,count(emp_id)
from employee em
right outer join months mo on ifnull(em.joining_date,'2010-01-01') < mo.start_date 
and ifnull(em.relieving_date,'2050-01-01') > mo.end_date
 where em.bill=1 and em.org_id=8
group by mo.month

这是我的月份表：

 id    start_date    end_date     month      year
'1', '2015-01-01', '2015-01-31', 'January', '2015'
'2', '2015-02-01', '2015-02-28', 'February', '2015'
'3', '2015-03-01', '2015-03-31', 'March', '2015'
'4', '2015-04-01', '2015-04-30', 'April', '2015'
'5', '2015-05-01', '2015-05-31', 'May', '2015'
'6', '2015-06-01', '2015-06-30', 'June', '2015'
'7', '2015-07-01', '2015-07-31', 'July', '2015'
'8', '2015-08-01', '2015-08-31', 'August', '2015'
'9', '2015-09-01', '2015-09-30', 'September', '2015'
'10', '2015-10-01', '2015-10-31', 'October', '2015'
'11', '2015-11-01', '2015-11-30', 'November', '2015'
'12', '2015-12-01', '2015-12-31', 'December', '2015'

这是我的员工表：

id    joining_date  relieving_date    bill      org_id  emp_id
1,       NULL,      NULL,           0,        8,        1
2, '2015-02-10',       NULL,        1,        8,       2
3, '2015-08-05', '2015-11-31',       1,       8,       3

这是我目前的输出：

 year   org_id month  count(emp_id)
'2015', '8', 'April', '2'
'2015', '8', 'August', '2'
'2015', '8', 'December', '2'
'2016', '8', 'February', '1'
'2016', '8', 'January', '1'
'2015', '8', 'July', '2'
'2015', '8', 'June', '2'
'2015', '8', 'March', '2'
'2015', '8', 'May', '2'
'2015', '8', 'November', '2'
'2015', '8', 'October', '3'
'2015', '8', 'September', '3'

我的预期输出是：

 year   org_id month  count(emp_id)
'2015', '8', 'April', '1'
'2015', '8', 'August', '2'
'2015', '8', 'December', '1'
'2016', '8', 'February', '0'
'2016', '8', 'January', '0'
'2015', '8', 'July', '1'
'2015', '8', 'June', '1'
'2015', '8', 'March', '1'
'2015', '8', 'May', '1'
'2015', '8', 'November', '1'
'2015', '8', 'October', '2'
'2015', '8', 'September', '2'

如果缓解日期不是他们的，则计数会自动增加。

任何帮助!!

Answer 1

select mo.year, mo.month, count(emp_id)
from employee em
right outer join months mo 
on 
  ifnull(em.joining_date,'2050-01-01') < mo.start_date 
  and ifnull(em.relieving_date,'2050-01-01') > mo.end_date
where 
  em.bill=1 and em.org_id=8
group by mo.month

MySql查询无法正常工作

1 个答案: