使用 GROUP BY SQL 选择多个列

Question

我试图从一列中选择最小日期值，同时按另一个具有多个重复值的非唯一 id 列进行分组，并且还希望显示满足前两个条件的相同行。原始数据库列如下所示：

['TransactionDate','TransactionStatusID','DateOfEntry','DateOfService','Amount','TransactionTypeID','PaymentTypeId','PostDate','BillID','ChargeDetailID']

第二张桌子看起来像：

['Amount', 'PracticeID', 'LoadDate', 'DateOfService', 'PerformingProvderID', 'CPTCodeID', 'ChargeDetailID']

我在“ChargeDetailID”上加入这两个表，例如：

SELECT  cd.PatientID, MIN(t.DateOfService) AS "Date Of Service"
FROM ChargeDetail as cd inner join transactions as t on cd.ChargeDetailID = t.ChargeDetailID
WHERE cd.PatientID IS NOT NULL
GROUP BY cd.PatientID   

我从这个查询中得到的结果：

|           PatientID|Date Of Service|
+--------------------+---------------+
|D37224C7-9157-4C5...|     2020-03-30|
|5E693AF8-8332-477...|     2014-01-07|
|8C071F5C-2210-4A6...|     2013-02-14|
|38B11DAE-3FF1-4AD...|     2012-03-14|
|7DB00C43-36F6-40E...|     2009-01-16|
|940EEC5C-4781-4EB...|     2016-12-08|

我想要的结果：

|           PatientID|Date Of Service|  cd.Amount| cd.BillID|
+--------------------+---------------+-----------+----------+
|D37224C7-9157-4C5...|     2020-03-30|   500     |10009
|5E693AF8-8332-477...|     2014-01-07|   250     |1492
|8C071F5C-2210-4A6...|     2013-02-14|  350      |15892
|38B11DAE-3FF1-4AD...|     2012-03-14|  222      |15596
|7DB00C43-36F6-40E...|     2009-01-16|  899      |20566
|940EEC5C-4781-4EB...|     2016-12-08|  650      |9566

Answer 1

您可以在 group by 中添加 cd.amount 和 cd.billid。但是要求不是很清楚。你也可以使用窗口函数。

SELECT  cd.PatientID, cd.Amount, cd.BillID, MIN(t.DateOfService) AS "Date Of Service"
FROM ChargeDetail as cd inner join transactions as t on cd.ChargeDetailID = t.ChargeDetailID
WHERE cd.PatientID IS NOT NULL
GROUP BY cd.PatientID , cd.Amount, cd.BillID

Answer 2

您可以使用如下窗口功能-

Select 
    PatientID
  , Amount
  , BillId
  , DateOfService As "Date Of Service"
from
 (SELECT  
     cd.PatientID
    ,cd.Amount
    ,cd.BillId
    ,t.DateOfService
    ,row_number() over(partition by cd.PatientID order by t.DateOfService asc) as seqnum
FROM ChargeDetail as cd inner join transactions as t 
on cd.ChargeDetailID = t.ChargeDetailID
WHERE cd.PatientID IS NOT NULL) t
Where t.seqnum = 1;

注意 MySQL 和 SqlServer 是 2 个不同的数据库，但是上述方法应该适用于两者。