Question

我在员工和他的同事数据下面有表格，我想在员工表中更新bucketid，如果有匹配的同事与其他员工。

这个例子中，

Employee = 101与Employee = 103同事（即c1）匹配，因此两者都应该具有相同的bucketid = 1（即两个bucketids的分钟）

和Employee = 102与Employee = 103同事（即c3）匹配，因此两者都应该具有相同的bucketid，但是在这里它应该更新为1作为employee = 102 bucketid刚刚更改为1.我们具有传递法依赖这个例子中的数据。

(i.e. a=b and b=c then a=c)

员工表：

EmployeeID  EmployeeName    BucketID
101         williams        1
102         williams        2
103         williams        3
104         williams        4

Employee_Colleague表：

EmployeeID  Colleague
101         c1
101         c2
102         c3
102         c4
103         c1
103         c3
104         c7

我尝试使用此更新查询

 update a2
 set BucketID = a1.BucketID
 from Employee a1
 inner join Emp_Colleagues c1 on a1.EmployeeID=c1.EmployeeID 
 inner join Employee a2 on a1.EmployeeName=a2.EmployeeName
 inner join Emp_Colleagues c2 on a2.EmployeeID=c2.EmployeeID
 where c1.Colleague=c2.Colleague and a1.BucketID <> a2.BucketID

它返回低于输出。

EmployeeID  EmployeeName    BucketID
101         williams        1
102         williams        1
103         williams        3
104         williams        4

但我想在Employee表中输出如下。

EmployeeID  EmployeeName    BucketID
101         williams        1
102         williams        1
103         williams        1
104         williams        4

Answer 1

我认为你不能在一个更新声明中这样做。但是，您可以使用循环来保持更新，直到没有任何内容可以更新：

declare @updates int = 1
while @updates > 0
begin
    update a2
        set BucketID = a1.BucketID
        from Employee a1
        inner join Emp_Colleagues c1 on a1.EmployeeID=c1.EmployeeID
        inner join Emp_Colleagues c2 on c1.Colleague=c2.Colleague
        inner join Employee a2 on a2.EmployeeID=c2.EmployeeID
        where a1.BucketID < a2.BucketID
    set @updates = @@ROWCOUNT
end

Answer 2

以下是您要查找的查询。

with CTE as
(
select EmployeeID as E1, EmployeeID as E2, cast('\' as varchar(MAX)) as list
from Employee
Union all
select E1, T2_2.EmployeeID, CTE.list +  CAST(E1 as varchar(MAX)) + '-' + CAST(T2_2.EmployeeID as varchar(MAX)) + '\'
from CTE
    inner join Employee_Colleague T2_1 ON CTE.E2 = T2_1.EmployeeID
    inner join Employee_Colleague T2_2 ON T2_1.Colleague = T2_2.Colleague
where CTE.list not like '%\' + CAST(E1 as varchar(MAX)) + '-' + CAST(T2_2.EmployeeID as varchar(MAX)) + '\' +'%'
)

Update T1_1
Set T1_1.BucketID = (select MIN(T1_2.BucketID) 
                        from Employee T1_2 
                            inner join CTE ON T1_1.EmployeeID = CTE.E1 AND T1_2.EmployeeID = CTE.E2
                    )
from Employee T1_1

使用传递数据自我加入更新查询

2 个答案: