向视图添加索引时出错

Posted 2023-02-16

【中文标题】向视图添加索引时出错

【英文标题】：Error adding an index to a view

【发布时间】：2011-05-11 05:38:38

【问题描述】：

我使用以下代码创建了一个视图

CREATE VIEW dbo.two_weeks_performance WITH SCHEMABINDING
AS 
  SELECT dbo.day_dim.date_time AS Date, 
         dbo.order_dim.quantity AS Target_Acheived
    FROM dbo.day_dim 
    JOIN dbo.order_fact ON dbo.day_dim.day_id = dbo.order_fact.day_id 
    JOIN dbo.branch_dim ON dbo.order_fact.branch_id = dbo.branch_dim.branch_id 
    JOIN dbo.order_dim ON dbo.order_fact.order_id = dbo.order_dim.order_id   
GROUP BY dbo.order_dim.quantity, dbo.day_dim.date_time` 

现在当我使用：

CREATE UNIQUE CLUSTERED INDEX two_weeks_performance_I ON two_weeks_performance (Date)

我收到一个错误：

无法创建索引，因为它的选择列表没有使用正确的 COUNT_BIG() 用法。考虑将 COUNT_BIG(*) 添加到选择中。

请帮我解决这个问题。

【参考方案1】：

该错误准确地告诉您必须做什么 - 将 COUNT_BIG(*) 添加到您的选择列表中。

来自Creating Indexed Views：

如果指定了 GROUP BY，则视图 选择列表必须包含 COUNT_BIG(*) 表达式和视图 定义不能指定 HAVING， 汇总、多维数据集或分组集。

CREATE VIEW dbo.two_weeks_performance WITH SCHEMABINDING
AS 
  SELECT dbo.day_dim.date_time AS Date, 
         dbo.order_dim.quantity AS Target_Acheived,
         COUNT_BIG(*) as Cnt 
    FROM dbo.day_dim 
    JOIN dbo.order_fact ON dbo.day_dim.day_id = dbo.order_fact.day_id 
    JOIN dbo.branch_dim ON dbo.order_fact.branch_id = dbo.branch_dim.branch_id 
    JOIN dbo.order_dim ON dbo.order_fact.order_id = dbo.order_dim.order_id   
GROUP BY dbo.order_dim.quantity, dbo.day_dim.date_time
GO
CREATE UNIQUE CLUSTERED INDEX two_weeks_performance_I ON two_weeks_performance (Date)