how to change effectively the In clause in SQL - sql-server

Question

we have a employee_master table and a Report_Filter Table, the Report_Filter contains different typs of filter the user enters for eg. status, employee code, nationaality etc. and this report_filter contains the user Information also. The table structure is like this Report_Filter( User_Id, Report_TYpe, Report_Code ) all are character fields. based on the users input the table will have values like
( 'User_1', 'STATUS', '01' )
( 'user_1', 'STATUS', '02' )
( 'User_1', 'EMP_CODE', 'ABC' )
( 'User_1', 'NATIONALITY', 'ALL' ) -- All means he want to see all the nationalities
now currently we are writing the query like this
Select Emp_code, Emp_Name, status, nationlity
From Empolyee_Master m
Where
('All' in ( select report_code from Report_Filter where user_id = #user_id and report_type='STATUS') or m.STATUS in ( select report_code from Report_Filter where user_id = #user_id and report_type='STATUS') ) and
or m.CATEGORY in ( select report_code from Report_Filter where user_id = #user_id and report_type='NATIONALITY') ) and
or m.emp_code in ( select report_code from Report_Filter where user_id = #user_id and report_type='EMP_CODE') )
there are other conditions also we are using, the problem is its take too much time because of the In clauses. how can we effectively change this code for improving performance
we are using MSSQL 2014

Answer 1

Instead of retrieving all values and then seeing if your value is part of it, you should filter by your value. Try if this helps (just one example):
replace
WHERE 'ALL' in (
select report_code from Report_Filter
where user_id = #user_id and report_type='STATUS'
)
with
WHERE EXISTS (
select 1 from Report_Filter
where user_id = #user_id and report_type='STATUS'
and report_code = 'ALL'
)
Now it would also help to include column report_code in an INDEX (you are using INDEXes, I hope?)
Update - to skip filtering in case of 'ALL', that can be done like this:
DECLARE #statusFilter VARCHAR(20) = ... -- 'ALL' or other value
SELECT ...
WHERE #statusFilter = 'ALL'
OR EXISTS (
select 1 from Report_Filter
where user_id = #user_id and report_type='STATUS'
and report_code = #statusFilter
)

Answer 2

You can try to do the filtering in advance:
(For your next question: Such a mockup should be done by you)
DECLARE #ReportFilter TABLE([user_id] VARCHAR(100),report_type VARCHAR(100),report_code VARCHAR(100));
INSERT INTO #ReportFilter VALUES
( 'User_1', 'STATUS', '01' )
,( 'user_1', 'STATUS', '02' )
,( 'User_1', 'EMP_CODE', 'ABC' )
,( 'User_1', 'NATIONALITY', 'ALL' );
DECLARE #Employee_Master TABLE(Emp_Code VARCHAR(100),Emp_Name VARCHAR(100), [status] VARCHAR(100), nationality VARCHAR(100));
INSERT INTO #Employee_Master VALUES
('ABC','test1','01','USA')
,('DEF','test2','99','GB')
,('ABC','test3','02','DE')
,('XYZ','test4','01','FRA');
--This is part of your query
DECLARE #user_id VARCHAR(100)='User_1';
WITH filterSTATUS AS
(
SELECT * FROM #ReportFilter WHERE [user_id]=#user_id AND report_type='STATUS'
AND NOT EXISTS(SELECT 1 FROM #ReportFilter WHERE [user_id]=#user_id AND report_type='STATUS' AND report_code='ALL')
)
,
filterEMPCODE AS
(
SELECT * FROM #ReportFilter WHERE [user_id]=#user_id AND report_type='EMP_CODE'
AND NOT EXISTS(SELECT 1 FROM #ReportFilter WHERE [user_id]=#user_id AND report_type='EMP_CODE' AND report_code='ALL')
)
,filterNATIONALITY AS
(
SELECT * FROM #ReportFilter WHERE [user_id]=#user_id AND report_type='NATIONALITY'
AND NOT EXISTS(SELECT 1 FROM #ReportFilter WHERE [user_id]=#user_id AND report_type='NATIONALITY' AND report_code='ALL')
)
SELECT *
FROM #Employee_Master AS em
WHERE (SELECT COUNT(*) FROM filterSTATUS)=0 OR em.[status] IN (SELECT x.report_code FROM filterSTATUS AS x)
AND (SELECT COUNT(*) FROM filterEMPCODE)=0 OR em.Emp_Code IN (SELECT x.report_code FROM filterEMPCODE AS x)
AND (SELECT COUNT(*) FROM filterNATIONALITY)=0 OR em.nationality IN (SELECT x.report_code FROM filterNATIONALITY AS x);
For the give set this returns
Emp_Code Emp_Name status nationality
ABC test1 01 USA
ABC test3 02 DE