Question

我有这个查询

SELECT
  schedule.JOB_NUMBER, max(schedule_milestone.actual_start_date), milestone.milestone_name
FROM
  schedule 
  inner join
   schedule_milestone on (schedule.schedule_id = schedule_milestone.schedule_id) inner join
   milestone on (milestone.milestone_id = schedule_milestone.milestone_id)
--where schedule.job_number = '024MGV002' using this for testing
group by schedule.job_number, milestone.milestone_name

我返回jobNumber，MaxDate和里程碑名称。

我想要它返回的是jobnumber，MaxDate和里程碑名称，但我只想为每个作业编号添加一行。我想要一个具有最新日期的里程碑。

因此，工作号码1234有4个不同的里程碑。我想要具有最大日期的里程碑的作业编号，日期和里程碑名称。

Answer 1

如果您没有使用MySQL，可以使用ROW_NUMBER()功能

否则

SELECT 
      S.JOB_NUMBER
    , SM.actual_start_date
    , M.milestone_name
FROM schedule S
JOIN schedule_milestone SM
  ON S.schedule_id = SM.schedule_id
JOIN milestone M
  ON M.milestone_id = SM.milestone_id
WHERE SM.actual_start_date = (  SELECT MAX(SM.actual_start_date)
                                FROM schedule iS
                                JOIN schedule_milestone iSM
                                  ON iS.schedule_id = iSM.schedule_id
                                JOIN milestone iM
                                  ON iM.milestone_id = iSM.milestone_id   
                                WHERE iS.job_number = S.job_number
                              )

请注意，如果多个里程碑共享同一start_date的{{1}}

，则会出现此问题

Answer 2

select * from (
Select JOB_NUMBER,dt,milestone_name,row_number() over (partition by JOB_NUMBER order by dt  desc ) as rownm
from (
SELECT
  schedule.JOB_NUMBER as JOB_NUMBER, milestone.milestone_name, max(schedule_milestone.actual_start_date) as dt
FROM
  schedule   schedule
  inner join
   schedule_milestone schedule_milestone
   on (schedule.schedule_id = schedule_milestone.schedule_id) 
   inner join
   milestone milestone on 
   (milestone.milestone_id = schedule_milestone.milestone_id)
group by schedule.job_number, milestone.milestone_name))
where rownm=1;

SQL，每个jobID只返回一行

2 个答案: