SQL IN Clause replacement Temp table - sql

Question

My query is :
Select *
from Person
where KV_CODE IN('','',''......1000 values here)
How to write this list of values in a temp table so that I can replace IN clause with a join to increase performance.
This list of values is coming on the basis of random selection by user and is stored in a Java collection.

Answer 1

Select * from Person P INNER JOIN #Temp T ON T.KV_CODE = P.KV_CODE
You can apply INNER JOIN on Temp Table similar to Normal Tables.

Answer 2

select *
from Person
where KV_CODE in (
select KV_CODE
from TempTable
)
This will compare the KV_CODE of Person to the KV_CODE of TempTable. If there are matches, it will intersect them, meaning your first select will print only those rows.
select *
from Person p
join TempTable tmp
on p.KV_CODE = tmp.KV_CODE
This will join the two tables and display the matching rows from both tables.
Unless your question is "how to populate a temporary table from a java collection"

Answer 3

Newer database solutions optimize this already. There is not much difference between IN clause and Join as optimizer figures out this aspect and execute query by appropriate path.
If you still wish, here is what you have to do.
if you are using Oracle,
you can create a session scope or transaction scope temporary table.
Insert data into this temporary table
Fire query like
SELECT *
FROM PERSONS T1,
TEMP_TABLE_NAME_HERE T2
WHERE T1.KV_CODE = T2.KV_CODE
However, a better solution is to avoid temp table creation during run time. You can actually create a permanent table in your application database with some unique key to identify your session (to isolate cross session impacts, i.e 2 users using same functionality).
CREATE TABLE KV_TEMP_TABLE
(SESSION_ID VARCHAR2(100),
KV_CODE VARCHAR2(100)
);
--Adjust datatypes suitably
Then your query should look like
SELECT * FROM PERSONS T1, KV_TEMP_TABLE T2
WHERE T2.SESSION_ID = ?
AND T1.KV_CODE = T2.KV_CODE
--Bind your session id
Before issuing this query, you have to populate data into KV_TEMP_TABLE using normal insert statements (along with a session id).

Answer 4

Use this example to populates a temp table :
DECLARE #t TABLE
(
EmployeeID INT,
Certs VARCHAR(8000)
)
INSERT #t VALUES (1,'B.E.,MCA, MCDBA, PGDCA'), (2,'M.Com.,B.Sc.'), (3,'M.Sc.,M.Tech.')
SELECT EmployeeID,
LTRIM(RTRIM(m.n.value('.[1]','varchar(8000)'))) AS Certs
FROM
(
SELECT EmployeeID,CAST('<XMLRoot><RowData>' + REPLACE(Certs,',','</RowData><RowData>') + '</RowData></XMLRoot>' AS XML) AS x
FROM #t
)t
CROSS APPLY x.nodes('/XMLRoot/RowData')m(n)
Once the temp table #t is populated, it can be used with JOINs to get the desired output.