Question

我有一张表，其中ID可以与多个帐单相关联。我需要做的是找到MAX结算金额，ID和最高（MAX）帐单的日期。问题是，在任何特定日期都可能有成千上万的人，数百人。

我的查询

select patientID, max(amountPaid) as maxPaid
from myTable
group by patientID

给我我需要的东西，减去日期。我试图解决这个问题是

select t.patientID, t.maxPaid, myTable.billDate
from myTable
inner join
(
select patientid, max(amountPaid) as maxPaid
from myTable
group by patientID
) as t on t.patientID=myTable.patientID and =t.maxPaid=myTable.maxPaid

给出的错误是invalid column name maxPaid。我尝试不给计算字段一个别名，但SQL Server也不接受myTable.max（amountPaid）。解决这个问题的最快方法是什么？提前谢谢。

Answer 1

您当前的方法存在的问题是，如果患者有两张最大金额的账单，您将同时获得这两种账单。

请改为尝试：

SELECT 
    patientid,
    amountPaid AS max_paid,
    billDate
FROM
(
    SELECT
        patientid,
        amountPaid,
        billDate,
        ROW_NUMBER() OVER (PARTITION BY patientid
                           ORDER BY amountpaid DESC) AS RowNumber
    FROM myTable 
) T1
WHERE T1.RowNumber = 1

即使患者有两张具有相同最大值amountpaid的账单，每位患者也会返回一行。

Answer 2

;WITH x AS (SELECT PatientID, BillDate, AmountPaid,
  rn = ROW_NUMBER() OVER (PARTITION BY PatientID ORDER BY AmountPaid DESC)
  FROM dbo.myTable
)
SELECT PatientID, BillDate, AmountPaid
FROM x
WHERE rn = 1;

Answer 3

根据您的描述，我认为您的意思是：

select t1.patientID, t2.maxPaid, t1.billDate
from myTable t1
inner join
(
    select patientid, max(amountPaid) as maxPaid
    from myTable
    group by patientID
) t2
on t1.patientID=t2.patientID 
and t1.amountPaid=t2.maxPaid

获得每位患者的最高账单

3 个答案: