如何从ration_card表计算成人和儿童

本文介绍了如何从ration_card表计算成人和儿童的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我想在ration_card中计算成人和小孩

ration_card（id，ration_card_number，姓名，年龄）

I want to count adult and child in ration_card

ration_card (id,ration_card_number,name,age)

insert into ration_card values('1','1001','ABC','50')
insert into ration_card values('2','1001','DEF','20')
insert into ration_card values('3','1001','GHI','5')
insert into ration_card values('4','1001','JK','10')

insert into ration_card values(5,1002,'ABC',50)
insert into ration_card  values(6,1002,'DEF',20)
insert into ration_card values(7,1002,'GHI',5)
insert into ration_card values(8,1002,'JK',10)

我的尝试：

What I have tried:

select count(name) as Adult from ration_card group by age having age>17

推荐答案

select count(*) as Adult from ration_card where age> 17
select count(*) as Child from ration_card where age< 17

SELECT Class, count(name) 
FROM (
      SELECT CASE WHEN age > 17 THEN 'Adults' ELSE 'Children' END AS Class, name 
      FROM ration_card) a
GROUP BY Class

SELECT
    Sum(CASE WHEN Age > 17 THEN 1 ELSE 0 END) As Adults,
    Sum(CASE WHEN Age <= 17 THEN 1 ELSE 0 END) As Children
FROM
    ration_card
;

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