按年龄分组和计数

Question

对于航行（年、船），我如何在标准 SQL 或 MS-ACCESS 中按年龄间隔对水手进行分组和计数？

YEAR    SHIP            SAILOR_AGE
2003    Flying dolphin  33
2003    Flying dolphin  33
2003    Flying dolphin  34
2001    Flying dolphin  23
2003    Flying dolphin  35
2001    Flying dolphin  38
2001    Flying dolphin  31
2003    Flying dolphin  36
2003    Columbine       41
2003    Columbine       42
2003    Flying dolphin  27
2003    Flying dolphin  51
2003    Flying dolphin  46

我尝试了什么：

SELECT YEAR, SHIP, SAILOR_AGE,  COUNT (*) as `NUMBERS` 
FROM TABLE
GROUP BY YEARS, SHIP, SAILOR_AGE;

它给我每年的水手人数：

示例：

YEAR |SHIP           |SAILOR_AGE  | NUMBERS
------------------------------------------
2003 | Flying dolphin| 33         |   2

如何按区间对水手年龄进行分组

示例：

From 20th to 40th year's old  
From 40th  to 60th year's old

Answer 1

您可以尝试使用 CASE 来指定以下年龄范围：

SELECT YEARS, SHIP, AgeRange, COUNT (*) as `NUMBERS` 
FROM (SELECT YEAR
            , SHIP
            , CASE WHEN SAILOR_AGE BETWEEN 21 AND 40 THEN '21-40'
                   WHEN SAILOR_AGE BETWEEN 41 AND 60 THEN '41-60'
                   ELSE 'XX-XX' -- anything goes here
              END as AgeRange
      FROM YourTable
)x
GROUP BY YEARS, SHIP, AgeRange;

Answer 2

如果你想要列中的值，你可以使用条件聚合：

SELECT YEAR, SHIP, COUNT(*) as NUMSAILORS,
       SUM(CASE WHEN SAILOR_AGE BETWEEN 21 AND 40 THEN 1 ELSE 0 END) as AGE_21_40,
       SUM(CASE WHEN SAILOR_AGE BETWEEN 41 AND 60 THEN 1 ELSE 0 END) as AGE_41_60
FROM TABLE
GROUP BY YEARS, SHIP;

Answer 3

您可以通过使用 CASE EXPRESSION 的单个查询来完成：

SELECT t.years,t.ship,
       CASE WHEN t.Sailor_age between 21 and 40 then 'From 20th to 40th'
            WHEN t.Sailor_age between 41 and 60 then 'From 40th to 60th'
            ELSE 'Other Ages'
       END as Range
FROM YourTable t
GROUP BY t.years,t.ship,CASE WHEN t.Sailor_age between 21 and 40 then 'From 20th to 40th' WHEN t.Sailor_age between 41 and 60 then 'From 40th to 60th' ELSE 'Other Ages' END
ORDER BY t.years,t.ship,Range

或者，如果您希望使用条件聚合将其作为单行：

SELECT t.years,t.ship,
       COUNT(CASE WHEN t.Sailor_age between 21 and 40 then 1 end) as Age_21_to_40,
       COUNT(CASE WHEN t.Sailor_age between 41 and 60 then 1 end) as Age_41_to_60,
FROM YourTable t
GROUP BY t.years,t.ship
ORDER BY t.years,t.ship

Answer 4

我认为实现这一目标的最佳方法是创建助手 table:

DECLARE @hlptbl TABLE(DescOfGrp VARCHAR(50), AgeFrom INT, AgeTo INT)
INSERT INTO @hlptbl (DescOfGrp, AgeFrom, AgeTo)
VALUES('20 to 40', 20, 40),
('41 to 60', 40, 60)

然后，您必须以这种方式加入数据：

SELECT t1.[Year], t1.SHIP, t2.DescOfGrp, COUNT(t1.SHIP) AS Number
FROM TableA As t1 INNER JOIN @hlptbl AS t2 ON 
           t1.SAILOR_AGE>=t2.AgeFrom AND t1.SAILOR_AGE <=t2.AgeTo
GROUP BY t1.[Year], t1.SHIP, t2.DescOfGrp

结果：

Year    SHIP    DescOfGrp   Number
2001    Flying dolphin  20 to 40    3
2003    Columbine       41 to 60    2
2003    Flying dolphin  20 to 40    6
2003    Flying dolphin  41 to 60    2

Answer 5

因此 - 给定标签 - 很可能是 Access SQL，你可以这样做：

SELECT 
    YEAR, 
    SHIP, 
    INT(SAILOR_AGE / 20) * 20 AS AgeGroup,  
    COUNT(*) As [NUMBERS]
FROM 
    TABLE
GROUP BY 
    YEAR, 
    SHIP, 
    INT(SAILOR_AGE / 20) * 20

按年龄分组和计数

Group and count by age breaks

sql

sqlite

ms-access

ms-access-2007

ms-access-2010