如何計算男女人數

[A - Zhi]

我有2個表格
table : service
serviceID clientID service
1 1 Call
2 1 Email
3 2 Call
4 3 Email
5 1 Email

Table : Client
ClientID Gendar birthday City
1 M ..
2 M ..
3 F
4 F
5 M

我需要計算出 email 服務的 男女人數（不能重復，比如clientID 1 我們 email 了2次，但是他是同1個人， 所以男人數只能+1

感謝各位了

[chenghangstar]

SELECT 
	B.Gendar
	,COUNT(DISTINCT A.clientID) AS CT
FROM service AS A
JOIN Client AS B ON A.clientID=B.clientID
WHERE A.service='email'
GROUP BY 

CT即是你所求的男女email服务的人数

[chenghangstar]

SELECT 
	B.Gendar
	,COUNT(DISTINCT A.clientID) AS CT
FROM service AS A
JOIN Client AS B ON A.clientID=B.clientID
WHERE A.service='email'
GROUP BY 
	B.Gendar

CT即是你所求的email服务的男女人数

[shoppo0505]

那就service table里面 distint clientID, 然后再 group by 一下client ID，用count（*）算出数量，然后再join client表格，最后再group by 性别

[jereco]

select count(distinct clintID) from ( select a.clientID,a.service,b.Gendar from service a left join Client b on a.clientID=b.ClientId ) c where service='Email' and Gendar='F'

[mspython]

select b. gender,count(distinct a.clientid) from service a,client b where a. service=’email’ and a. clientid=b. clientid group by a. gender

[锟斤拷锟斤拷]

SELECT COUNT(*) FROM CLIENT a WHERE a.CLIENTID IN (SELECT CLIENTID FROM SERVICE WHERE SERVICE = 'Email') AND a.GENDER = 'M'