如何在列，其中的值是X

Question

执行计数有与SQL执行计数操作的方式，其中列等于X 理想的情况是单独计数，当同一列等于Y和再针对z？

Answer 1

我相信下面的（较短）的声明应为MySQL工作：

SELECT COUNT(val='X'), COUNT(val='Y'), COUNT(val='Z') FROM ... 

Answer 2

像这样的事情？

select 
    sum(case when val = 'x' then 1 else 0 end) as countX 
    ,sum(case when val = 'y' then 1 else 0 end) as countY 
    ,sum(case when val = 'z' then 1 else 0 end) as countZ 
from table 

Answer 3

SELECT yourcolumn, COUNT(*) AS cnt 
FROM yourtable 
WHERE yourcolumn IN ('X', 'Y', 'Z') 
GROUP BY yourcolumn 

Answer 4

我建议如下：

SELECT YourColumn, COUNT(<Any Column of your table>) 
FROM YourTable 
GROUP BY YourColumn