我有一个表格[order],其中一个简单的选择以一种奇怪的方式显示了估计行数和实际行数之间的主要差异。
在这种情况下,一般估计行数与实际行数相比偏斜,这完全具有讽刺意味。此外,“执行次数”为 1。
询问 :
SELECT
ord.paymentmode AS [HowTheyPaid],
ord.id AS [OrderId],
ord.ISBackEndSystemMigrated,
ord.ISDuplicate,
ord.ISMerged
FROM
DedicatedDentalPlans_Stage.dbo.[order] ord
WHERE
ISBackEndSystemMigrated=0
AND ISDuplicate = 1
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桌子
USE [DedicatedDentalPlans_Stage]
GO
IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[DF_Order_ISBackEnd]') AND type = 'D')
BEGIN
ALTER TABLE [dbo].[Order] DROP CONSTRAINT [DF_Order_ISBackEnd]
END
GO
IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[DF__Order__ISDuplica__382F5661]') AND type = 'D')
BEGIN
ALTER TABLE [dbo].[Order] DROP CONSTRAINT [DF__Order__ISDuplica__382F5661]
END
GO
IF EXISTS (SELECT * …Run Code Online (Sandbox Code Playgroud)