搜索，獲得的各種數據

Question

的計數這裏是我的表emp：

+---------+------------------+ 
| emp  | id  | color | 
+---------+------------------+ 
| hary | 123  | red | 
+---------+------------------+ 
| lary | 125  | green | 
+---------+------------------+ 
| gary | 038  | red | 
+---------+------------------+ 
| Kris | 912  | blue | 
+---------+------------------+ 
| hary | 123  | red | 
+---------+------------------+ 
| Ronn | 334  | green | 
+---------+------------------+ 

現在我想找出每種顏色即紅，綠，藍的計數;

在這方面，我試着寫下來的where color like '%bl%',like '%ree%',like %ed%.方面的查詢，並希望這一結果

+--------------------------+ 
| red | blue | green  | 
+--------------------------+ 
| 3 | 1 | 2   | 
+--------------------------+ 

我已經試過這件事情：

select count(case when color='green' then 1 end) as Green,count(case when 
color='blue' then 1 end) as Blue,count(case when color='Red' then 1 end) as Red from emp; 

我不想硬編碼他們的名字（因爲我將在我的代碼jdbc中使用它）。 我會很感激任何關於這個問題的意見。

Answer 1

select color,count(*) clrCount 
from emp 
group by color 

與where子句

select color,count(*) clrCount 
from emp where (color like '%bl%' or color like '%ree%') 
group by color 

Answer 2

可以使用

select color,count(*) from emp group by color;