如何在使用子查询时提高查询性能

Question

查询的第一部分会抓取Policy的{​​{1}}，Premiums和Effective日期。 第二部分创建Expiration，第三部分（最终Calendar声明）返回按SELECT和Month细分的收入 一切正常，只需3秒即可显示结果。 但是我需要过滤Year要使用的内容，基本上我需要摆脱没有PolicyNumber的{​​{1}}。因此，对于查询的第一部分，我放置了PolicyNumber子句：

@ClassCode

感谢@Prdp用户我有这样的陈述：Case语句将为列表中存在的ClassCode生成1，否则将生成NULL。现在，每个PolicyNumber的count聚合将计为1。通过设置= 0，我们可以确保PolicyNumber在给定列表中没有任何ClassCode。

在该查询永远消失之后，因为WHERE在SSRS报告中可以有超过200 WHERE State IN ('CA','NV','AZ') AND PolicyNumber IN ( SELECT PolicyNumber FROM tblClassCodesPlazaCommercial GROUP BY PolicyNumber HAVING COUNT (CASE WHEN ClassCode NOT IN (@ClassCode) THEN 1 END)=0 ) 。

有趣的是，这两种说法都可以单独运作。但是当我一起使用它们（在@ClassCode中放置ClassCodes子句时，执行将永远执行。 有没有办法告诉引擎做查询的第一部分，即

WHERE

然后仅针对已过滤的策略计算和细分收入。

我的整个代码如下：

cte policy_data

提高性能的最佳方法是什么？ 我在两个表的; WITH Earned_to_date AS ( SELECT Cast(EOMONTH (GETDATE(), -1) AS DATE) AS Earned_to_date ), policy_data AS ( SELECT PolicyNumber , Cast(PolicyEffectiveDate AS DATE) AS PolicyEffectiveDate , Cast(PolicyExpirationDate AS DATE) AS PolicyExpirationDate , WrittenPremium , State FROM PlazaInsuranceWPDataSet WHERE State IN ('CA','NV','AZ') /* -------This statement gives me trouble ----------------------*/ AND PolicyNumber IN ( SELECT PolicyNumber FROM tblClassCodesPlazaCommercial GROUP BY PolicyNumber HAVING COUNT (CASE WHEN ClassCode NOT IN (5151) THEN 1 END)=0 ) ) 上创建了; WITH Earned_to_date AS ( SELECT Cast(EOMONTH (GETDATE(), -1) AS DATE) AS Earned_to_date ), policy_data AS ( SELECT PolicyNumber , Cast(PolicyEffectiveDate AS DATE) AS PolicyEffectiveDate , Cast(PolicyExpirationDate AS DATE) AS PolicyExpirationDate , WrittenPremium , State FROM PlazaInsuranceWPDataSet WHERE State IN ('CA','NV','AZ') /* -------This statement gives me trouble ----------------------*/ AND PolicyNumber IN ( SELECT PolicyNumber FROM tblClassCodesPlazaCommercial GROUP BY PolicyNumber HAVING COUNT (CASE WHEN ClassCode NOT IN (@ClassCode) THEN 1 END)=0 ) ) , digits AS ( SELECT digit FROM (VALUES (0), (1), (2), (3), (4) , (5), (6), (7), (8), (9)) AS z2 (digit) ), numbers AS ( SELECT 1000 * d4.digit + 100 * d3.digit + 10 * d2.digit + d1.digit AS number FROM digits AS d1 CROSS JOIN digits AS d2 CROSS JOIN digits AS d3 CROSS JOIN digits AS d4 ), calendar AS ( SELECT DateAdd(month, number, '1753-01-01') AS month_of , DateAdd(month, number, '1753-02-01') AS month_after FROM numbers ), policy_dates AS ( SELECT PolicyNumber , CASE WHEN month_of < PolicyEffectiveDate THEN PolicyEffectiveDate ELSE month_of END AS StartRiskMonth , CASE WHEN PolicyExpirationDate < month_after THEN PolicyExpirationDate WHEN Earned_to_date.Earned_to_date < month_after THEN Earned_to_date ELSE month_after END AS EndRiskMonth , DateDiff(day, PolicyEffectiveDate, PolicyExpirationDate) AS policy_days , WrittenPremium FROM policy_data JOIN calendar ON (policy_data.PolicyEffectiveDate < calendar.month_after AND calendar.month_of < policy_data.PolicyExpirationDate) CROSS JOIN Earned_to_date WHERE month_of < Earned_to_date ) SELECT Year(StartRiskMonth) as YearStartRisk, Month(StartRiskMonth) as MonthStartRisk, c.YearNum,c.MonthNum, convert(varchar(7), StartRiskMonth, 120) as RiskMonth, sum(WrittenPremium * DateDiff(day, StartRiskMonth, EndRiskMonth) / policy_days) as EarnedPremium FROM tblCalendar c LEFT JOIN policy_dates l ON c.YearNum=Year(l.StartRiskMonth) AND c.MonthNum = Month(l.StartRiskMonth) AND l.StartRiskMonth BETWEEN '01-01-2015' AND '12-31-2016' WHERE c.YearNum Not IN (2017) GROUP BY convert(varchar(7), StartRiskMonth, 120), Year(StartRiskMonth) , Month(StartRiskMonth), c.YearNum,c.MonthNum ORDER BY c.YearNum,c.MonthNum 索引。但仍然没有。 就像我说的，在我看来，如果SQL引擎将处理第一部分（PolicyNumber过滤）需要3秒，然后再执行第二部分（计算那些PolicyNumber＆＃39; s）需要另外3秒 - 这将是真棒。 但我是DBA的新手，所以我不确定它是否可能。 有什么建议？ 感谢

执行计划::

最终结果：

Answer 1

您必须使代码更具可读性。通过临时表而不是cte将其拆分为更小的块。

你的麻烦：

HAVING COUNT (CASE WHEN ClassCode NOT IN (5151) THEN 1 END)=0

如果您的HCOING COUNT（TRUE - > 1）中的ClassCode为5000。

如果您的HCOING COUNT（FALSE - ＆gt; NULL）中的ClassCode为5151。

应在分组前过滤：

WHERE ClassCode IN (5151) -- and check index