Using in clause in query with many values

--SPLIT Technique

DECLARE @x AS XML=''

DECLARE @Param AS VARCHAR(1000) = 'Ind,Hary,Gu'

SET @x = CAST('<A>'+ REPLACE(@Param,',','</A><A>')+ '</A>' AS XML)

;WITH CTE AS
(
	SELECT t.value('.', 'VARCHAR(10)') Value FROM @x.nodes('/A') AS x(t)
)
SELECT  n.* FROM note n
CROSS APPLY
(
    SELECT TOP 1 Value FROM
	CTE r
	WHERE r.Value  = n.conversation_id
)y

--

Select allOpen in new window

HI,
In the temp table approach are you also counting the time to insert all the values in the temporary table... ?
So what i understand is that
1) insert all ids into temp table and then query using join
will be faster than
2) select * from .... where id in (....)

Can you also ping some article or link to understand this behavior why is this so ?
Also is the performance difference significant ?
Thanks

So basically what we are doing it we are first creating a temp table and insert all the values in there, This will be very fast because we are not disturbing the Main database.
Then we are joining this temp table with the user table [note in your case]. Once you join you will get records which are common in both the tables, note and the temp table.
If we directly do In with the Main table then it will be slow.


Have you tried this.. [A sample by Sharath.]

CREATE TEMPORARY TABLE temp_ids (conversation_id int);
INSERT INTO temp_ids VALUES ('id1'),('id2'),('id3'); -- insert all your ids here

-- Then you can join this temporary table to your actual table
SELECT * FROM note n
INNER  JOIN temp_ids t on t.conversation_id  = n.conversation_id

--Put a where clause whatever row is not required. OR Paste your complete query , will try to modify it.

Hi Rohit,

Do you need more help with this question? A feedback will be appreciated. :)

Regards,

Pawan