Question

我有一个名为'sales'的表，其中包含以下字段

salesid (type: int)
stime (type: datetime)
status (type: enum, values: remaining OR cancelled OR done)
... and other fields

我需要一个可以输出为

的查询

SalesDate     TotalSales    TotalDone      TotalRemaining     TotalCancelled
2010-11-06       10             5                3                 2
2010-11-06       15             14                1                 0

任何人都知道怎么做到这一点？
感谢帮助，谢谢。

Answer 1

您可以使用条件求和来获得所需的结果。

select stime  as sales_date
      ,sum(1) as total_sales
      ,sum(case when status = 'remaining' then 1 else 0 end) as total_done
      ,sum(case when status = 'cancelled' then 1 else 0 end) as total_remaining
      ,sum(case when status = 'done'      then 1 else 0 end) as total_cancelled
  from sales
 group by stime;

您还可以使用COUNT（ expr ）并利用它不包含NULLS的事实，但我个人认为上述最佳方式表达了开发人员的意图。

Answer 2

使用CASE中的SELECT语句，使用状态值remaining, cancelled和done

创建伪列

SELECT     
     date(stime),
     COUNT(salesid),
     SUM(CASE status WHEN 'done' THEN 1 ELSE 0 END) as TotalDone,
     SUM(CASE status WHEN 'remaining' THEN 1 ELSE 0 END) as TotalRemaining, 
     SUM(CASE status WHEN 'cancelled' THEN 1 ELSE 0 END) as TotalCancelled 
FROM  sales
GROUP BY date(stime)

注意：这是我试图引用的内容。我认为这应该工作，但我无法访问MySQL来尝试语法并验证它。对于那个很抱歉。但这应该让你前进。

MySQL在单个查询中多次计数

2 个答案: