无法在架构绑定视图上创建索引

Question

无法在以下架构绑定上创建索引 view.It 是从另一个视图 (v_prod_manu_sub) 创建的。显示以下错误消息：

Cannot create index on view "dbo.V_PROD_MANU" because it references derived table "X" (defined by SELECT statement in FROM clause). Consider removing the reference to the derived table or not indexing the view.

如何更改以下查询以创建索引？

ALTER VIEW [dbo].[V_PROD_MANU] WITH SCHEMABINDING AS
SELECT X.PRODUCT, CAST(RIGHT(TEXT_CODE,LEN(F_TEXT_CODE)-1) AS VARCHAR(30)) AS TEXT_CODE,
    CAST(SUBSTRING(RIGHT(PHRASE,LEN(F_PHRASES)-1),9,LEN(F_PHRASE)-3) AS varchar(700)) AS PHRASE
    FROM (
    SELECT V1.PRODUCT,
    (SELECT ',' + V2.TEXT_CODE FROM dbo.V_PROD_MANU_SUB V2 WHERE V1.PRODUCT = V2.PRODUCT ORDER BY V2.F_COUNTER  FOR XML PATH('')) AS TEXT_CODE,
    (SELECT ' |par|par ' + V3.F_PHRASE FROM dbo.V_PROD_MANU_SUB V3 WHERE V1.PRODUCT = V3.PRODUCT ORDER BY V3.F_COUNTER FOR XML PATH('')) AS PHRASE
FROM dbo.V_PROD_MANU_SUB  V1 GROUP BY V1.PRODUCT)X

输出：

Product         TEXT_CODE                PHRASE 
00-021      MANU0043,MANU0050     Inc |par  Pharmaceuticals Group |par  235 East 5nd Street |par usa |par 1-800-123-000

Answer 1

通常人们使用 STUFF() 来删除前导逗号，而不是这些混乱的转换和 LEN() 计算。例如：

SELECT V1.PRODUCT,
    TEXT_CODE = STUFF
    (
      (
        (SELECT ',' + V2.TEXT_CODE 
           FROM dbo.V_PROD_MANU_SUB AS V2 
           WHERE V1.PRODUCT = V2.PRODUCT 
           ORDER BY V2.F_COUNTER  
           FOR XML PATH(''), 
           TYPE).value('./text()[1]','nvarchar(max)')
      ),
    1,1,N'')
FROM dbo.V_PROD_MANU_SUB AS V1 
GROUP BY V1.PRODUCT;

-- much easier in SQL Server 2017 with STRING_AGG()

但这似乎与您首先需要具体化逗号分隔列表的原因无关，无论它是否有前导逗号。

索引视图通常是过早优化的一种形式。本质上你是在说，“查询这些数据的成本将远远大于维护它的成本。”你知道吗？如何？您的工作负载平衡是多少（读：写）？现在查询有多慢？它多久运行一次？更新需要多长时间？

如果您确实知道这一点，那么您会更幸运地通过触发器手动将其具体化为您自己的 table。由于各种原因，索引视图很可能成为死胡同。

无法在架构绑定视图上创建索引

Not able to create index on schema binding view

subquery

indexed-view

sql-server-2012