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我想强制SQL服务器使用存在子句的散列匹配如下。对于EXISTS子句SQL Server查询提示
FROM
[Dbo].[360 Nrc Data] AS [nrc]
WHERE
[CALENDAR_DATE] BETWEEN @START_DATE AND @End_Date
AND EXISTS (SELECT 1
FROM [staging].[FACT_DTV_RETENTION_EVENT_STEP_1] AS [fact]
WHERE [fact].[CD_PORTFOLIO_ID] = [nrc].[Cd_Portfolio_Id]
AND [fact].[Event_Date] = [nrc].[CALENDAR_DATE])
GROUP BY
[Calendar_Date], [Cd_Portfolio_Id])
正常的方式来强制查询提示如下,但是左半加入的效率比具有加入
[_fact_date_and_portfolio] AS [fact]
inner hash join
[dbo].[360 TA Offer] AS [offr]
你为什么要强制哈希匹配?适当的索引可能会更快。 –
做> 10M连接,我想强迫SQL Server得到行估计错误的时间很多。 –