Question

我有2个表，任务和员工。这些都在关系数据库中。

我想要做的是使用4个staffID（1,2,3,4）更新Tasks表中的StaffID列，并在迭代中执行，最终结果将是：

那么StaffID＆＃39; 1＆＃39;将有任务1,5,9等，以及所有其他staffID做同样的事情。到目前为止，我的查询看起来像这样，但我确定我错过了很多东西：

update Tasks
set StaffID = 2
where

这就是我所拥有的，在此之后，我对我需要做什么感到难过。对此的任何帮助或指向如何执行此操作的文档链接都会很棒。

Answer 1

create table task as
WITH tasks as 
(select 1 taskid,1 staffid, 'Task 1' title,getdate()-1 createdDate union all
select 2 taskid,1 staffid, 'Task 2' title,getdate()-2 createdDate union all
select 3 taskid,1 staffid, 'Task 3' title,getdate()-3 createdDate union all
select 4 taskid,1 staffid, 'Task 4' title,getdate()-4 createdDate union all
select 5 taskid,1 staffid, 'Task 5' title,getdate()-5 createdDate union all
select 6 taskid,1 staffid, 'Task 6' title,getdate()-6 createdDate union all
select 7 taskid,1 staffid, 'Task 7' title,getdate()-7 createdDate union all
select 8 taskid,1 staffid, 'Task 8' title,getdate()-8 createdDate union all
select 9 taskid,1 staffid, 'Task 9' title,getdate()-9 createdDate 
)
SELECT * FROM tasks

update task
set staffid =  case when mod(taskid,4) =1 then 1
                 when mod(taskid,4) =2 then 2
                 WHEN mod(taskid,4) =3 then 3
                 WHEN mod(taskid,4) =0 then 4
            end from task b
where taskid=b.taskid;

Answer 2

如果您知道taskid没有间隙，那么对其进行算术将解决您的问题。否则，您可以使用row_number()：

with toupdate as (
      select t.*, row_number() over (order by t.taskid) as seqnum
      from tasks t
     )
update toupdate
    set staffid = ((seqnum - 1) % 4) + 1;

Answer 3

您可以使用此功能为员工分配任务，请阅读评论以适应您的需求（如果需要）。

DECLARE @AmountStaffToAssign INT = 4

;WITH SequentialStaffIDs AS
(
    -- Get a sequential ID asigned to each of your StaffID (if not already sequential)
    SELECT TOP (@AmountStaffToAssign)
        S.StaffID,
        SequentialID = ROW_NUMBER() OVER (ORDER BY (SELECT NULL))
    FROM
        Staff AS S
    -- You can filter your staff to reassign here and also order them
),
SequentialTaskIDs AS
(
    -- Get a sequential ID asigned to each of your TaskID (if not already sequential)
    SELECT
        S.TaskID,
        SequentialID = ROW_NUMBER() OVER (ORDER BY (SELECT NULL))
    FROM
        Task AS S
    -- You can filter you tasks to be assigned here
),
TaskReassignment AS
(
    SELECT
        T.TaskID,
        T.SequentialID,
        StaffSequentialID = ((T.SequentialID - 1) % @AmountStaffToAssign) + 1
    FROM
        SequentialTaskIDs AS T
)
UPDATE T SET
    StaffID = S.StaffID
FROM
    Task AS T
    INNER JOIN TaskReassignment AS R ON T.TaskID = R.TaskID
    INNER JOIN SequentialStaffIDs AS S ON R.StaffSequentialID = S.SequentialID

Answer 4

以下是我的答案：https://sqleditor.net/q/rk6YcdEtM

UPDATE T SET StaffID = S.StaffID
FROM (
  SELECT ROW_NUMBER() OVER (ORDER BY TaskID) % (SELECT COUNT(*) FROM Staff) AS seq, StaffID FROM Tasks
 ) T
INNER JOIN (
  SELECT ROW_NUMBER() OVER (ORDER BY StaffID) % (SELECT COUNT(*) FROM Staff) AS seq, StaffID FROM Staff
) S ON T.seq = S.seq;
GO

您可以在此处尝试更多详细信息：https://sqleditor.net/q/rk6YcdEtM

TSQL - 如何使用迭代

4 个答案: