Question

例如，我这样做

select * from tblClientInfo
with some condition

有2条记录：

 ClientID=001, Salary=500. 
 ClientID=001, Salary=550.

如何仅选择薪水最高的记录？仅供参考，可能还有2条以上的记录。

我知道如何进行升序排序，但是我不知道如何选择其中之一。

这是我的代码

Select A.AgencyID,19,291,
BETAC.FirstName,BETAC.LastName,BETAC.Phone,BETAC.EMailAddress,BETAC.AnnualIncome,BETAC.Occupants,BETAC.Children2,
BETAC.Children5,ISNULL(BETAC.Children17, 0) ,BETAC.Elderlys,BETAC.Disableds,
0,0,TKFT.FuelTypeID,TKV1.LookupValueID,
BETAC.LandlordName,BETAC.LandlordAddress,BETAC.LandlordCity,BETAC.LandlordState,BETAC.LandlordZip,
BETAC.LandlordPhone,BETAC.HeatInRent,BETAC.DHWInRent,'2018/01/01',BETAC.FirstPrintedDate,
BETAC.StatusDate,NULL,NULL,ISNULL(BETAC.PovertyLevel,0),
BETAC.HighUse,BETAC.HighBurden,ISNULL(BETAC.Section8Housing,0),NULL,NULL,0,BETAC.IsRequestWNZ,
BETAC.SignatureConfirmation,BETAC.MoveInOut,CO.CountyID,
0,0,0,1,BETAC.BenefitAmount,0,1,U.UserID,BETAC.ClientNumber 

from LABeta_FA.dbo.tblClientInfo as BETAC
join LABeta_FA.dbo.tgAgency as BETAA on BETAA.AgencyID=BETAC.AgencyID
join tgAgency as A on BETAA.Phone COLLATE DATABASE_DEFAULT=A.Phone COLLATE DATABASE_DEFAULT
join LABeta_FA.dbo.tgClientStatus as LACS on LACS.ClientStatusID=BETAC.ClientStatusID
--join tlkpValues as TKV on TKV.DisplayName COLLATE DATABASE_DEFAULT=LACS.ClientStatus COLLATE DATABASE_DEFAULT
join LABeta_FA.dbo.tlkpHeatingSource as LATKHS on LATKHS.HeatingID=BETAC.FuelTypeID
join tlkpFuelType as TKFT on TKFT.FuelType COLLATE DATABASE_DEFAULT=LATKHS.HeatingSource COLLATE DATABASE_DEFAULT
join LABeta_FA.dbo.tlkpBuildingType as TKBT on TKBT.BuildingTypeID=BETAC.BuildingTypeID
join tlkpValues as TKV1 on TKV1.DisplayName COLLATE DATABASE_DEFAULT=TKBT.BuildingType COLLATE DATABASE_DEFAULT
join LABeta_FA.dbo.tgUser as LAU on LAU.UserID=BETAC.UserID
join tgUser as U on U.UserName COLLATE DATABASE_DEFAULT=LAU.UserName COLLATE DATABASE_DEFAULT
join LABeta_FA.dbo.tgCounty as LACO on LACO.CountyID=BETAC.CountyID
join tgCounty as CO on CO.County COLLATE DATABASE_DEFAULT=LACO.County COLLATE DATABASE_DEFAULT
where BETAC.LastDate>'01/01/2018' and
BETAC.FirstName='Brandon'

然后结果就像

brandon benefitamount=400 date=2018/01/01
brandon benefitamount=450 date=2019/01/01

我希望结果是最高的收益金额。

Answer 1

使用max()

 select max(Salary) from tblClientInfo where ClientID=001

如果要选择表的所有列，则可以使用子查询

 select * from tblClientInfo 
 where Salary=(select max(Salary) from tblClientInfo where ClientID=001
            ) and ClientID=001

Answer 2

ROW_Number()像波纹管一样

;With cte as (
select *, ROW_NUMBER() Over(partition by ClientID order by Salary DESC) as RN  from tblClientInfo
)
Select * from cte where RN=1

Answer 3

您可以使用这个：

Select * from tblClientInfo where ClientID=001 order by Salary desc limit 1

Answer 4

您将使用order by和仅提取一行的某种方法。在标准SQL中，这将是：

select t.*
from t
where clientID = '001'
order by t.salary dec
fetch first 1 row only;

并非所有数据库都支持fetch first。在某些情况下，您使用top (1)。在其他情况下，limit甚至更深奥的构造。

Answer 5

使用行号作为子查询：

row_number是提供结果并对其进行排序的功能。有序列表根据分区（clientID）重新开始，并根据顺序提供顺序（第一个Benefitamount desc和第二个dte desc）。

select *
from(
      select [all of your columns and they must have alias]
          , rn = Row_NUMBER() over (partition by ClientID Order by benefitamount desc, dte desc)
      from [your tables and joins]
   ) a
where a.rn=1 -- returns the ordered result from above

Answer 6

您只需要使用max（Salary）和一个子查询进行分组，这将帮助您为每个分组提供完整记录

  Select * from table where 
    clientId,Salary    
    IN ( Select clientId, max(Salary) from 
     table 
    group by clientId)

在查询结果中选择较大值的记录

6 个答案: