如何获取SQL查询：SHOW记录通过量

Question

我想从一个表格式显示销售数量：

Sales    qty 
------------------------------------------ 
Sales > 50,000 500 
Sales < 2000  200 
Sales > 15,000 600 
------------------------------------------ 

如何创建呢？

我可以写一个数量的查询where > 50000但在这种情况下有三个50,000,2000,15,000，我怎么能在结果中显示所有这些？

Answer 1

一种方式来做到这一点是简单地使用union all：

select 'Sales > 50,000' as sales, 
     count(*)   as qty 
     where sales > 50000 
union all 
select 'Sales < 2,000' as sales, 
     count(*)   as qty 
     where sales < 2000 
union all 
select 'Sales > 15,000' as sales, 
     count(*)   as qty 
     where sales > 15000 and sales <= 50000 

需要注意的是最后一个，我假设你希望它独家从上述50,000（否则有60,000的sales显示一排在这两个部分）。

Answer 2

SELECT SUM(A), 
    SUM(B), 
    SUM(C) 
FROM 
    (SELECT 
    CASE 
     WHEN Sales > 50000 
     THEN 1 
     ELSE 0 
    END AS A, 
    CASE 
     WHEN Sales < 2000 
     THEN 1 
     ELSE 0 
    END AS B, 
    CASE 
     WHEN Sales > 15000 
     THEN 1 
     ELSE 0 
    END AS C 
    FROM table 
)