将数据总结为年份范围

Question

我想sumarise中的数据，并且很难找到用于分组数据的方法。

我有一个表，名为汽车

CarID CarMake CarModel CarYear 
1  Ford  Mondeo 2000 
2  Ford  Mondeo 2002 
3  Ford  Mondeo 2003 
4  Ford  Mondeo 2005 

我希望能集团这一数据显示为

CarMake CarModel CarYearRange 
Ford  Mondeo 2000-2003 
Ford  Mondeo 2005-2005 

我一直在使用的最小和最大生产这种然而，这失败如果尝试例如，这辆车不是在一年之间制造的。

Answer 1

select carmake, carmodel, 
case when caryear >= 2000 and caryear <=2003 then '2000-2003' 
    when caryear >= 2005 and caryear <=2005 then '2005-2005' 
end t 
from car 
group by carmake, carmodel , t 

为fiddle demo

Answer 2

我假定（也许brashly），你的样本数据中包含一个错误，该范围应该是2000年，2002- 2003年，和2005年因为有2001年或没有模型2004年如果我是正确的，那么这将工作：

WITH CTE AS 
( SELECT Cars.CarMake, 
      Cars.CarModel, 
      [FirstYear] = Cars.CarYear, 
      [LastYear] = Cars.CarYear, 
      [Recursion] = 1 
    FROM Cars 
    UNION ALL 
    SELECT CTE.CarMake, 
      CTE.CarModel, 
      CTE.[FirstYear], 
      [LastYear] = Cars.CarYear, 
      [Recursion] = [Recursion] + 1 
    FROM CTE 
      INNER JOIN Cars 
       ON CTE.CarMake = Cars.CarMake 
       AND CTE.CarModel = Cars.CarModel 
       AND CTE.[LastYear] = Cars.CarYear - 1 
), MaxCTE AS 
( SELECT CarMake, 
      CarModel, 
      FirstYear, 
      LastYear, 
      Recursion, 
      [MaxRecursion] = MAX(Recursion) OVER(PARTITION BY CarMake, CarModel, FirstYear) 
    FROM CTE 
) 
SELECT MaxCTE.CarMake, 
     MaxCTE.CarModel, 
     [CarYearRange] = CAST(FirstYear AS VARCHAR(4)) + ' - ' + CAST(LastYear AS VARCHAR(4)) 
FROM MaxCTE 
WHERE Recursion = MaxRecursion 
AND  NOT EXISTS 
     ( SELECT 1 
      FROM MaxCTE ex 
      WHERE MaxCTE.CarMake = ex.CarMake 
      AND  MaxCTE.CarModel = ex.CarModel 
      AND  MaxCTE.FirstYear > ex.FirstYear 
      AND  MaxCTE.LastYear = ex.LastYear 
     ) 

SQL Fiddle Example

编辑

如果我已经正确地解释了要求，使用RICHARD的KIWI的答案。它比矿井好得多！

Fiddle for the improved solution

SELECT CarMake, 
     CarModel, 
     [StartYear] = MIN(CarYear), 
     [EndYear] = MAX(CarYear) 
FROM ( SELECT *, 
        [Offset] = CarYear - ROW_NUMBER() OVER (PARTITION BY CarMake, CarModel ORDER BY CarYear) 
      FROM Cars 
     ) x 
GROUP BY CarMake, CarModel, Offset 
ORDER BY CarMake, CarModel, StartYear 

Answer 3

在SQL Server中，可以使用类似于这样：

select distinct carmake, 
    carmodel, 
    case 
    when caryear >= 2000 and caryear <= 2003 then '2000-2003' 
    when caryear >= 2005 and caryear <= 2005 then '2005-2005' 
    end CarYearRange 
from yourtable 

见SQL Fiddle with Demo

Answer 4

从您的需求GarethD的解释得到暗示，这里是我的查询来获得所需的结果。我强烈建议将范围显示为2个不同的列，并让前端代码合并它们以供显示（如果需要）。

select carmake, 
     carmodel, 
     min(caryear) startyear, 
     max(caryear) endyear 
from (
    select *, 
     offset= caryear-row_number() over (partition by carmake, carmodel 
              order by caryear) 
    from cars 
) x 
group by carmake, carmodel, offset 
order by carmake, carmodel, startyear