CASE Statement causing execute time to sky rocket - sql-server

Question

There are two distinct databases where I work. In creating a report (utilizing TSQL) to share between departments, it was requested to have a field to show the information from the primary database (information kept on the college's database) had also been inputted into a second database (that a specific department uses for information communications with federal program). Without checking the second database with the case statement the query for the rest of the information takes less than a second. With the case statement (in which CTEs where created to conduct the check), it has run for 15 minutes and not finished before I manually ended the execution. Here is the code (CASE statement currently commented out):
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
Any insights much appreciated, thanks!

Answer 1

It's hard to give a definitive answer here without knowing what your data and indexes look like. If you can share your the execution plan for both versions of your query it would be way easier to give you a clear answer.
You can share you execution plans here: https://www.brentozar.com/pastetheplan/
Without the execution plan here are a couple of ideas to try:
EXISTS often performs better than IN/NOT IN
CASE WHEN EXISTS (SELECT * FROM POWERFAIDS_CHECK WHERE CHECK_ID = AWARDED_SCHOLARSHIPS.CHECK_ID) THEN [...]
Adding a new CTE that contains the subset of data you need might help:
), VALID_CHECK_IDS AS ( SELECT DISTINCT CHECK_ID FROM POWER_FAIDS_CHECK )
Then use this CTE in your case statement.
Add a second join to POWERFAIDS_CHECK
LEFT JOIN POWERFAIDS_CHECK AS VALIDCHECKID ON AWARDED_SCHOLARSHIPS.CHECK_ID = POWERFAIDS_CHECK.CHECK_ID
and update your case to
CASE WHEN VALIDCHECKID.CHECK_ID IS NOT NULL THEN 'No' ELSE 'Yes' [...]