Question

对于航行（年份，船舶），如何在标准SQL或MS-ACCESS中按年龄间隔对水手进行分组和统计？

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;

它给了我每年的水手数量：

示例：

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

小组水手如何按时间间隔分组

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id指定以下年龄范围：

CASE

Answer 2

如果您想要列中的值，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

由于这个 - 给定标签 - 很可能是Access SQL，你可以这样：

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

Answer 4

您可以使用CASE EXPRESSION进行单个查询：

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 5

我想说实现这一目标的最佳方法是创建帮助表：

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

按年龄分组和计数

5 个答案: