SQL中的条件公用表表达式（CTE）

我的代码如下所示。我试图实现动态排序顺序，在SortOrder参数上使用IF或Case When。

如果@SortOrder等于'sortorder'，则注释行应该是活动的。我试图加上If Else的陈述，但我失败了......

你能帮忙吗？

CREATE PROCEDURE [dbo].[ProductCategory_SelectHierarchy] 
    @SortOrder varchar(30) 
AS 
    SET NOCOUNT ON; 

WITH Categories (Id,ParentId,SortOrder,RowOrder) as 
(
     SELECT parentCategory.Id, 
         parentCategory.ParentId, 
         parentCategory.SortOrder, 
         --cast(REPLACE(STR(parentCategory.SortOrder, 8), ' ', '0') as varchar(30)) 'RowOrder' 
         cast(CAST(DATEPART(YEAR, parentCategory.DateCreated) as varchar(4)) + 
         CAST(DATEPART(MONTH, parentCategory.DateCreated) as varchar(2)) + 
         CAST(DATEPART(DD, parentCategory.DateCreated) as varchar(2)) + 
         CAST(DATEPART(HOUR, parentCategory.DateCreated) as varchar(2)) as varchar(50)) 'RowOrder' 
     FROM  ProductCategories parentCategory 
     WHERE  ParentId = 0 

     UNION ALL 

     SELECT childCategories.Id, 
         childCategories.ParentId, 
         childCategories.SortOrder, 
         --cast(Categories.RowOrder + REPLACE(STR(childCategories.SortOrder, 8), ' ', '0') as varchar(30)) 'RowOrder' 
         cast(Categories.RowOrder + '/' + CAST(DATEPART(YEAR, childCategories.DateCreated) as varchar(4)) + 
         CAST(DATEPART(MONTH, childCategories.DateCreated) as varchar(2)) + 
         CAST(DATEPART(DD, childCategories.DateCreated) as varchar(2)) + 
         CAST(DATEPART(HOUR, childCategories.DateCreated) as varchar(2)) as varchar(50)) 'RowOrder' 
     FROM  ProductCategories childCategories 
     JOIN  Categories 
     ON   childCategories.ParentId = Categories.Id 
) 

SELECT pc.*, Categories.RowOrder 
FROM Categories 
INNER JOIN ProductCategories pc ON pc.Id = Categories.Id 
ORDER BY RowOrder

来源

2010-06-14 MartinHN

您应该能够像这样排序的：

ORDER BY 
    CASE 
     WHEN @SortOrder = 'date_column' THEN CONVERT(VARCHAR(20), date_column, 120) 
     WHEN @SortOrder = 'customer_id' THEN RIGHT(REPLICATE('0', 20) + CAST(customer_id AS VARCHAR(20)), 20) 
     WHEN @SortOrder = 'name' THEN name 
     ELSE sort_order 
    END

的关键是让所有排序的列（或表达式）的最后形成相同的数据类型。

来源

2010-06-14 16:46:07

无法正常工作。虽然，你的伪代码不会做我想要实现的。我希望@SortOrder可以像'createdate'，'salescount'，'name'或'custom'一样更静态。每种情况都应该导致不同的SQL语句。 – MartinHN 2010-06-14 17:14:47

我刚刚编辑了答案，现在我对您要查找的内容有了更清晰的了解。 – 2010-06-14 17:23:22

哦，我应该按照从句的顺序来做。我改变了我的代码，所有4列添加到数据集，这样做是为了通过： ORDER BY CASE \t WHEN @SortOrder = 'NameSortedOrder'，那么Categories.NameSortedOrder \t WHEN @SortOrder =“SalesCountOrder 'THEN Categories.SalesCountOrder \t WHEN @SortOrder ='DateCreatedOrder'THEN Categories.DateCreatedOrder \t ELSE Categories.SortOrder END – MartinHN 2010-06-14 18:35:39

SQL中的条件公用表表达式（CTE）

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