CASE 语句导致天空火箭执行时间

如何解决CASE 语句导致天空火箭执行时间

我工作的地方有两个不同的数据库。在创建报告（使用 TSQL）以在部门之间共享时，要求有一个字段来显示来自主要数据库（保存在学院数据库中的信息）的信息也已输入到第二个数据库（特定部门使用的）用于与联邦计划的信息通信）。如果不使用 case 语句检查第二个数据库，查询其余信息的时间不到一秒钟。使用 case 语句（在其中创建 CTE 以进行检查），它已经运行了 15 分钟，但在我手动结束执行之前还没有完成。这是代码（CASE 语句目前已注释掉）：

With POWERFAIDS_CHECK as
        (
        Select distinct NAME_MASTER.ID_NUM,(CAST (NAME_MASTER.ID_NUM as VARCHAR) + CAST (EX_SCHOLARSHIP_RECIPIENTS.AID_ELEMENT as VARCHAR) ) as CHECK_ID
        
            From NAME_MASTER
            JOIN EX_SCHOLARSHIP_RECIPIENTS on NAME_MASTER.ID_NUM = EX_SCHOLARSHIP_RECIPIENTS.ID_NUM
            JOIN SCHOLARSHIP on EX_SCHOLARSHIP_RECIPIENTS.AID_ELEMENT = SCHOLARSHIP.AID_ELEMENT
            JOIN PF_FUND_CDE_MSTR on EX_SCHOLARSHIP_RECIPIENTS.AID_ELEMENT = PF_FUND_CDE_MSTR.RPT_CATEGORY
            JOIN PowerFAIDS_Production.dbo.student on NAME_MASTER.ID_NUM = PowerFAIDS_Production.dbo.student.alternate_id
            JOIN PowerFAIDS_Production.dbo.funds on  PF_FUND_CDE_MSTR.FUND_CDE = PowerFAIDS_Production.dbo.funds.fund_ledger_number
            JOIN PowerFAIDS_Production.dbo.stu_award_year on PowerFAIDS_Production.dbo.student.student_token = PowerFAIDS_Production.dbo.stu_award_year.student_token
            JOIN PowerFAIDS_Production.dbo.stu_award on PowerFAIDS_Production.dbo.stu_award_year.stu_award_year_token = PowerFAIDS_Production.dbo.stu_award.stu_award_year_token
            JOIN YEAR_TERM_TABLE on (YEAR_TERM_TABLE.YR_CDE = EX_SCHOLARSHIP_RECIPIENTS.YR_CDE) and (YEAR_TERM_TABLE.TRM_CDE = EX_SCHOLARSHIP_RECIPIENTS.TRM_CDE)

            Where EX_SCHOLARSHIP_RECIPIENTS.YR_CDE = '2021'
            and EX_SCHOLARSHIP_RECIPIENTS.TRM_CDE = 'FA'
            and YEAR_TERM_TABLE.TRM_BEGIN_DTE = PowerFAIDS_Production.dbo.stu_award.award_period_begin_dt
            and EX_SCHOLARSHIP_RECIPIENTS.AWARD_AMT = PowerFAIDS_Production.dbo.stu_award.actual_amt
            and stu_award.status = 'A'
        ),AWARDED_SCHOLARSHIPS as

        (Select distinct NAME_MASTER.ID_NUM,(NAME_MASTER.FIRST_NAME + ' ' + NAME_MASTER.LAST_NAME) as STUDENT_NAME,SCHOLARSHIP.DESCRIPTION,Format (EX_SCHOLARSHIP_RECIPIENTS.AWARD_AMT,'C','en-us') as AWARD_AMT,EX_SCHOLARSHIP_RECIPIENTS.COMMENTS,YR_DESC,TRM_DESC,EX_SCHOLARSHIP_RECIPIENTS.AID_ELEMENT,(CAST (NAME_MASTER.ID_NUM as VARCHAR) + CAST (EX_SCHOLARSHIP_RECIPIENTS.AID_ELEMENT as VARCHAR) ) as CHECK_ID,NAME_MASTER.LAST_NAME,NAME_MASTER.FIRST_NAME
        
        From NAME_MASTER
            JOIN EX_SCHOLARSHIP_RECIPIENTS on NAME_MASTER.ID_NUM = EX_SCHOLARSHIP_RECIPIENTS.ID_NUM
            JOIN SCHOLARSHIP on EX_SCHOLARSHIP_RECIPIENTS.AID_ELEMENT = SCHOLARSHIP.AID_ELEMENT
            JOIN YEAR_DEF on EX_SCHOLARSHIP_RECIPIENTS.YR_CDE = YEAR_DEF.YR_CDE
            JOIN TERM_DEF on EX_SCHOLARSHIP_RECIPIENTS.TRM_CDE = TERM_DEF.TRM_CDE
            Where EX_SCHOLARSHIP_RECIPIENTS.TRM_CDE = 'FA'
            and EX_SCHOLARSHIP_RECIPIENTS.YR_CDE = '2021'
            and EX_SCHOLARSHIP_RECIPIENTS.AID_ELEMENT not between '5000' and '5999'
    )

    Select distinct AWARDED_SCHOLARSHIPS.ID_NUM,STUDENT_NAME,AWARDED_SCHOLARSHIPS.DESCRIPTION,AWARDED_SCHOLARSHIPS.AWARD_AMT,--CASE
                --  WHEN AWARDED_SCHOLARSHIPS.CHECK_ID not in (Select CHECK_ID from POWERFAIDS_CHECK)
                --  THEN 'No'
                --  ELSE 'Yes'
                --END as Processed_FA_Award,AWARDED_SCHOLARSHIPS.COMMENTS,AWARDED_SCHOLARSHIPS.YR_DESC,AWARDED_SCHOLARSHIPS.TRM_DESC,AWARDED_SCHOLARSHIPS.LAST_NAME,AWARDED_SCHOLARSHIPS.FIRST_NAME
    From AWARDED_SCHOLARSHIPS
    LEFT OUTER JOIN POWERFAIDS_CHECK on AWARDED_SCHOLARSHIPS.ID_NUM = POWERFAIDS_CHECK.ID_NUM
    Where AWARDED_SCHOLARSHIPS.ID_NUM in (Select ID_NUM from AWARDED_SCHOLARSHIPS)

    Order by AWARDED_SCHOLARSHIPS.DESCRIPTION,LAST_NAME,FIRST_NAME

非常感谢任何见解，谢谢！

解决方法

如果不知道您的数据和索引是什么样的，就很难在这里给出明确的答案。如果您可以共享您的查询的两个版本的执行计划，那么给您一个明确的答案会更容易。

您可以在这里分享您的执行计划：https://www.brentozar.com/pastetheplan/

如果没有执行计划，这里有几个可以尝试的想法：

1. EXISTS 通常比 IN/NOT IN 表现更好

CASE WHEN EXISTS (SELECT * FROM POWERFAIDS_CHECK WHERE CHECK_ID = AWARDED_SCHOLARSHIPS.CHECK_ID) THEN [...]

2. 添加包含您需要的数据子集的新 CTE 可能会有所帮助：

),VALID_CHECK_IDS AS ( SELECT DISTINCT CHECK_ID FROM POWER_FAIDS_CHECK )

然后在你的案例陈述中使用这个 CTE。

3. 向 POWERFAIDS_CHECK 添加第二个连接

LEFT JOIN POWERFAIDS_CHECK AS VALIDCHECKID ON AWARDED_SCHOLARSHIPS.CHECK_ID = POWERFAIDS_CHECK.CHECK_ID

并将您的案例更新为

CASE WHEN VALIDCHECKID.CHECK_ID IS NOT NULL THEN 'No' ELSE 'Yes' [...]