Question

这是我的疑问：

select 
    Sales.SaleID,
    Sales.StartSaleDate,
    Sales.EndSaleDate,
    Sales.SalePercent,
    COUNT(LessonID) as TotalLesson,
    Sales.Status,
    Sales.ExpiredStatus,
    Sales.SalePrice,
    Sales.IsSpecial
FROM 
    Sales
LEFT JOIN 
    SaleLessons ON SaleLessons.SaleID = Sales.SaleID 
GROUP BY
    Sales.Status, Sales.IsSpecial, Sales.StartSaleDate, Sales.EndSaleDate,
    Sales.SalePercent, Sales.SaleID, Sales.ExpiredStatus, Sales.SalePrice 
ORDER BY 
    Sales.StartSaleDate DESC

Answer 1

    create view ViewSchema.ViewName
    as
select Sales.SaleID,
       Sales.StartSaleDate,
       Sales.EndSaleDate,
       Sales.SalePercent,
       COUNT(LessonID) as TotalLesson,
       Sales.Status,
       Sales.ExpiredStatus,
       Sales.SalePrice,
       Sales.IsSpecial
from Sales
LEFT JOIN SaleLessons
    ON SaleLessons.SaleID = Sales.SaleID 
group by Sales.Status,
         Sales.IsSpecial,
         Sales.StartSaleDate,
         Sales.EndSaleDate,
         Sales.SalePercent,
         Sales.SaleID,
         Sales.ExpiredStatus,
         Sales.SalePrice

您真的不需要ORDER BY子句，以后可以在从视图中提取数据时使用它。

此外，这是一个关于这个主题的非常丰富的答案 - https://stackoverflow.com/a/15188437/7119478

如何使用Count（）创建SQL视图

1 个答案: