SQL COUNT国籍与多位艺术家和艺术家的数量，国籍

Question

艺术家

（名字，姓氏，国籍）

Miro      Joan      Spanish      
Kandinsky     Wassily      Russian      
Klee      Paul      German       
Matisse      Henri      French       
Chagall      Marc      French       
Sargent      John Singer     United States     
Tobey      Mark      United States     
Horiuchi     Paul      United States     
Graves      Morris      United States     
Julio      Bloxham Smythe    Spanish      
Basher      Bigmouth     Spanish  

我必须列出所有的民族与代表多位艺术家在数据库中，和国籍的艺术家的数量

所以输出应该是

Spanish   3 
United states 4 
French   2 

Answer 1

HAVING是你的朋友

SELECT NATIONALITY, COUNT(*) 
FROM ARTIST 
GROUP BY NATIONALITY 
HAVING COUNT(*)>1 

Answer 2

select nationality, 
     count(firstname) as artists -- counts the artists 
from mytable 
group by nationality -- we group on this, because we want to aggregate the other info 
having count(firstname) >1 -- applies a condition AFTER the count 

Answer 3

你可以使用一个group by条款适用每国籍一组，然后having条款只保留民族与多位艺术家：

SELECT nationality, COUNT(*) 
FROM  artist 
GROUP BY nationality 
HAVING COUNT(*) > 1 

Answer 4

使用分组方式

SELECT count(*),`NATIONALITY` 
FROM `ARTIST` 
GROUP BY `NATIONALITY` 
HAVING count(FIRSTNAME) > 1 

Answer 5

使用具有是没有必要的，简单的GROUP BY会做：

SELECT NATIONALITY,COUNT(*) FROM ARTIST GROUP BY NATIONALITY; 

Answer 6

你需要使用什么是计数功能。尝试https://www.tutorialspoint.com/sql/sql-count-function.htm

我认为你需要的是一个普遍的计数。它是如此简单：

Count(*) 

我想这个问题已被问过很多次，所以为了节省时间下次尝试搜索文档。