Sql按列的最大值选择不同的行

我在尝试为每个城市名称选择一行时遇到问题。这是我得到的以下收藏：

这是我目前的疑问：

select pl.PlaceId,
       pl.Name,
       pop.NumberOfPeople,
       pop.Year
from dbo.Places pl
inner join dbo.Populations pop
    on pop.PlaceId = pl.PlaceId
where pop.NumberOfPeople >= 1000
and pop.NumberOfPeople <= 99999

---

我试图让它只选择一个城市一次，但使用最近的日期。因此，在上图中，我只会看到2016年的阿贝维尔，而不是2015年。我认为我需要进行分组或子查询，以使结果平坦化。如果有人对我如何处理这个问题有任何建议，我们将不胜感激。

假设您使用的是SQLSERVER，那么您可以使用Rownumber

;with cte
as
(select pl.PlaceId,
       pl.Name,
       pop.NumberOfPeople,
       pop.Year,
row_number() over(partition by pl.Name order by year desc) as rownum
from dbo.Places pl
inner join dbo.Populations pop
    on pop.PlaceId = pl.PlaceId
where pop.NumberOfPeople >= 1000
and pop.NumberOfPeople <= 99999
)
select * from cte where rownum=1

---

假设您使用的是SQLSERVER，则可以使用Rownumber

;with cte
as
(select pl.PlaceId,
       pl.Name,
       pop.NumberOfPeople,
       pop.Year,
row_number() over(partition by pl.Name order by year desc) as rownum
from dbo.Places pl
inner join dbo.Populations pop
    on pop.PlaceId = pl.PlaceId
where pop.NumberOfPeople >= 1000
and pop.NumberOfPeople <= 99999
)
select * from cte where rownum=1

---

下面的查询用于此目的

CREATE TABLE #TEMP_TEST
(
PlaceId INT,
Name VARCHAR(50),
NumberOfPeople INT,
YEAR INT
)

INSERT INTO #TEMP_TEST 
SELECT 1,'Abbeville',2603,2016
UNION
SELECT 5,'Alabester',32948,2016
UNION
SELECT 9,'Aubum',63118,2016
UNION
SELECT 1,'Abbeville',2402,2015
UNION
SELECT 5,'Alabester',67902,2017



SELECT PlaceId, Name, NumberOfPeople, YEAR  FROM
 (
   SELECT ROW_NUMBER() OVER (PARTITION BY PlaceId ORDER BY YEAR DESC) RNO, 
          PlaceId, Name, NumberOfPeople, YEAR 
   FROM #TEMP_TEST
 )T
WHERE RNO = 1

DROP TABLE  #TEMP_TEST

---

下面的查询用于此目的

CREATE TABLE #TEMP_TEST
(
PlaceId INT,
Name VARCHAR(50),
NumberOfPeople INT,
YEAR INT
)

INSERT INTO #TEMP_TEST 
SELECT 1,'Abbeville',2603,2016
UNION
SELECT 5,'Alabester',32948,2016
UNION
SELECT 9,'Aubum',63118,2016
UNION
SELECT 1,'Abbeville',2402,2015
UNION
SELECT 5,'Alabester',67902,2017



SELECT PlaceId, Name, NumberOfPeople, YEAR  FROM
 (
   SELECT ROW_NUMBER() OVER (PARTITION BY PlaceId ORDER BY YEAR DESC) RNO, 
          PlaceId, Name, NumberOfPeople, YEAR 
   FROM #TEMP_TEST
 )T
WHERE RNO = 1

DROP TABLE  #TEMP_TEST