Question

我有这张桌子：

wp_register_script

一些示例数据：

wp_enqueue_script

我有以下步骤：

CREATE TABLE [dbo].[Handshake]
(
    [Report Year] [varchar](100) NULL,
    [Status] [varchar](100) NULL,
    [Update Time] [datetime] NULL,
    [Process Time] [datetime] NULL
) ON [PRIMARY]
GO

仅当我未在Validations SELECT语句中包含此部分时，该过程才有效：Report Year Status Update Time Process Time ---------------------------------------------------------------- Test Loading 2020-09-22 12:53:41.417 NULL 2020 1+7 Loaded 2020-09-22 12:46:41.417 NULL 2020 2+7 Loaded 2020-09-21 21:18:25.130 NULL，因此选择了最近的更新时间记录，例如

DECLARE
    @ReportYearCmd VARCHAR(1000),
    @CosCountCmd VARCHAR(1000),
    @FranchiseCountCmd AS VARCHAR(1000),
    @ProductCountCmd AS VARCHAR(1000);

WITH Validations AS 
(
    SELECT TOP 1 * 
    FROM [Handshake] 
    WHERE [Status] <> 'Loading' 
      AND [Update Time] = (SELECT MAX([Update Time]) FROM Handshake)
)
UPDATE Validations 
SET @ReportYearCmd = CASE 
                        WHEN Report_Year_Count = 0 
                           THEN NULL 
                           ELSE 'SELECT DISTINCT [Report Year] AS [Report Year] FROM [Fact] WHERE NOT EXISTS ( SELECT * FROM [Report Year] WHERE [Report Year].[Report Year] = [Fact].[Report Year] );'
                     END,
    @CosCountCmd = CASE 
                      WHEN COS_Count = 0 
                         THEN NULL 
                         ELSE 'SELECT DISTINCT [Country Code] AS [COS - Country Code] FROM [Fact] WHERE NOT EXISTS ( SELECT * FROM [COS] WHERE [COS].[Country Code] = [Fact].[Country Code] );' 
                   END,
    @FranchiseCountCmd = CASE WHEN  Franchise_Count = 0 THEN NULL 
        ELSE 'SELECT DISTINCT [Style Code] AS [Franchise - Style Code] FROM [Fact] WHERE NOT EXISTS ( SELECT * FROM [Franchise] WHERE [Franchise].[Style Code] = [Fact].[Style Code] );' 
    END,
    @ProductCountCmd = CASE WHEN Product_Count = 0 THEN NULL 
        ELSE 'SELECT DISTINCT [Style Code] AS [Product - Style Code] FROM [Fact] WHERE NOT EXISTS ( SELECT * FROM [Product] WHERE [Product].[Style Code] = [Fact].[Style Code] );' 
    END,
    [Status] = CASE
        WHEN ( Report_Year_Count = 0 AND COS_Count = 0 AND Franchise_Count = 0 AND Product_Count = 0 ) THEN 'Good'
        ELSE 'Rejects'
    END
FROM 
    [Validations] 
OUTER APPLY 
    (SELECT 
         ISNULL((SELECT COUNT(*) FROM [Fact] 
                 WHERE NOT EXISTS (SELECT * FROM [Report Year] WHERE [Report Year].[Report Year] = [Fact].[Report Year] ) ), 0 ) AS [Report_Year_Count],
        ISNULL( ( SELECT COUNT(*) FROM [Fact] WHERE NOT EXISTS ( SELECT * FROM [COS] WHERE [COS].[Country Code] = [Fact].[Country Code] ) ), 0 ) AS [COS_Count],
        ISNULL( ( SELECT COUNT(*) FROM [Fact] WHERE NOT EXISTS ( SELECT * FROM [Franchise] WHERE [Franchise].[Style Code] = [Fact].[Style Code] ) ), 0 ) AS [Franchise_Count],
        ISNULL( ( SELECT COUNT(*) FROM [Fact] WHERE NOT EXISTS ( SELECT * FROM [Product] WHERE [Product].[Style Code] = [Fact].[Style Code] ) ), 0 ) AS [Product_Count]

) AS [ValidationCounts];

当我包含...WHERE [Status] <> 'Loading'...时，什么也没发生！

期望：查询应获取此记录：

Test        Loading      2020-09-22 12:53:41.417    NULL

但这不是...为什么？

Answer 1

如果您想要最新的非加载状态，则不需要子查询。您可以仅在带有where子句的非加载行上使用过滤器，然后在order by降序日期上使用过滤器，并仅保留top (1)行：

WITH validations AS (
    SELECT TOP (1) * 
    FROM [Handshake] 
    WHERE [Status] <> 'Loading' 
    ORDER BY [Update Time] DESC
)
UPDATE validations ...

Answer 2

SELECT MAX( [Update Time] ) FROM Handshake的结果为 2020-09-22 12：53：41.417

现在您的查询是

SELECT TOP 1 * FROM [Handshake] WHERE [Status] <> 'Loading' AND [Update Time] = '2020-09-22 12:53:41.417'

当您评估以上查询时，您会看到没有记录在更新时间2020-09-22 12：53：41.417加载状态

正确的查询应该是

SELECT TOP 1 * FROM [Handshake] h 
WHERE [Status] <> 'Loading' AND 
  [Update Time] = ( 
    SELECT MAX( [Update Time] ) 
    FROM Handshake hi where hi.Status = h.Status)

为什么某些Where子句被忽略？

2 个答案: