Question

表1如下：

Name    Number  Month   Year    Fee_Paid
Ravi    1       1       2010    100
Raju    2       1       2010    200
Kumar   3       1       2010    300
Ravi    1       2       2011    100
Raju    2       2       2011    200
Kumar   3       2       2011    300
Ravi    1       3       2012    100
Raju    2       3       2012    200
Kumar   3       3       2012    300

结果应如下：

Name    Number  Month   Year    Fee_Paid
Ravi    1       3       2012    100
Raju    2       3       2012    200
Kumar   3       3       2012    300

结果应显示最新的年份和月份，包括该期间的姓名，编号和费用。请帮助我。

Answer 1

如果你想要每个名字的最后一行，不管上个月他们的是哪个月：

;WITH x AS 
(
    SELECT Name, Number, [Month], [Year], [Fee_Paid],
      rn = ROW_NUMBER() OVER 
      (PARTITION BY Name ORDER BY [Year] DESC, [Month] DESC)
    FROM dbo.Table1
)
SELECT Name, Number, [Month], [Year], [Fee_Paid]
FROM x
WHERE rn = 1
ORDER BY Number;

如果您希望找到上一年/月组合中的所有行，无论名称如何，查询只会略有不同：

;WITH x AS 
(
    SELECT Name, Number, [Month], [Year], [Fee_Paid],
      rn = DENSE_RANK() OVER (ORDER BY [Year] DESC, [Month] DESC)
    FROM #x
)
SELECT Name, Number, [Month], [Year], [Fee_Paid]
FROM x
WHERE rn = 1
ORDER BY Number;

这两个查询都给出了你似乎想要的结果，但其中一个可能只是巧合才是正确的。

Answer 2

这是非CTE解决方案：

select HighestYear.* from (
  select v1.* from visitors v1
  left join visitors v2
  on v1.number = v2.number and v1.year < v2.year
  where v2.year is null
) HighestYear
left join visitors v3
on HighestYear.number = v3.number and HighestYear.year = v3.year
and HighestYear.month < v3.month
where v3.month is null

Example with more data

Answer 3

SELECT
   Details.Name,
   Details.Number,
   Details.Month,
   Details.Year,
   Details.Fee_Paid
FROM
   (
   SELECT
      Name,
      MAX(Year) AS Year,
      MAX(Month) AS Month
   ) AS MaxValues
INNER JOIN MyTable AS Details ON
   Details.Name = MaxValues.Name
   AND Details.Year = MaxValues.Year
   AND Details.Month = MaxValues.Month

查找最近一个月，包括其他领域的年份

3 个答案: