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[rpljava]

我想用一条sql实现，下边的功能：

create table test_age(
id number(2),
age number(6));
insert into test_age
values(1, 25);
insert into test_age
values(2, 30);
insert into test_age
values(3, 45);
insert into test_age
values(4, 50);
希望的得到的查询结果是：

年龄段 人数
-------- -------
20-30 2
31-40 1
41-50 2

[boydgmx]

SELECT CASE WHEN age BETWEEN 20 AND 30 THEN '20-30' WHEN age BETWEEN 31 AND 40 THEN '31-40' WHEN age BETWEEN 41 AND 50 THEN '41-50' END,
COUNT(*)
FROM test_age
GROUP BY CASE WHEN age BETWEEN 20 AND 30 THEN '20-30' WHEN age BETWEEN 31 AND 40 THEN '31-40' WHEN age BETWEEN 41 AND 50 THEN '41-50' END
/

[boydgmx]

SELECT DECODE(
TRUNC((AGE-1)/10),
1,'20-30',
2,'20-30',
3,'31-40',
4,'41-50'
),COUNT(*)
FROM TEST_AGE
GROUP BY DECODE(
TRUNC((AGE-1)/10),
1,'20-30',
2,'20-30',
3,'31-40',
4,'41-50'
);

[boydgmx]

我给你的方法一种是CASE 一种是DECDOE，这就是常用的两种了，仔细看看吧

[luoshi1982]

boydgmx(梦霄) 大蝦，居然還能寫case語句，能介紹一下類似的例子麼？不勝感激！

[boydgmx]

CASE WHEN 条件 THEN 值 [WHEN 条件 THEN 值] [ELSE 值] END

[wangzk0206]

up
good study.....