How to apply trim function inside this query [duplicate] - sql

Question

Below is simple sql query to select records using in condition.
--like this I have 6000 usernames
select * from tblUsers where Username in ('abc ','xyz ',' pqr ',' mnop ' );
I know there are LTrim & Rtrim in sql to remove the leading trailing spaces form left & right respectively.
I want to remove the spaces from left & right in all the usernames that I am supplying to the select query.
Note:-
I want to trim the values that I am passing in the in clause.(I don't want to pass LTrim & RTrim to each value passed).
There are no trailing space in the records but value that I am passing in the clause is copied from excel & then pasted in Visual Studio. Then using ALT key I put '(single quote) at the left & right sides of the string. Due to this some strings has spaces in the right side trailing.
How to use the trim function in the select query?
I am using MS SQL Server 2012

Answer 1

If I understand your question correctly you are pasting from Excel into an IN clause in an adhoc query as below.
The trailing spaces don't matter. It will still match the string foo without any trailing spaces.
But you need to ensure that there are no leading spaces.
As the source of the data is Excel why not just do it all there?
You can use formula
= CONCATENATE("'",TRIM(SUBSTITUTE(A1,"'","''")),"',")
Then copy the result (from column B in the screenshot above) and just need to trim off the extra comma from the final entry.

Answer 2

You can do like this:
select * from tblUsers where LTRIM(RTRIM(Username)) in (ltrim(rtrim('abc')),ltrim(rtrim('xyz')),ltrim(rtrim('pqr')),ltrim(rtrim('mnop')));
However, if you have permission to update the database. Please remove all the spaces in your Username field. It is really not good to do the query like this.

Answer 3

One way to tackle your problem and still be able to benefit from an index on username is to use a persisted computed column:
Setup
-- drop table dbo.tblUsers
create table dbo.tblUsers
(
UserId INT NOT NULL IDENTITY(1, 1) CONSTRAINT PK_UserTest PRIMARY KEY,
Username NVARCHAR(64) NOT NULL,
UsernameTrimmed AS LTRIM(RTRIM(Username)) PERSISTED
)
GO
-- other columns may be included here with INCLUDE (col1, col2)
CREATE INDEX IDX_UserTest ON dbo.tblUsers (UsernameTrimmed)
GO
insert into dbo.tblUsers (Username) VALUES ('abc '),('xyz '),(' pqr '), (' mnop '), ('abc'), (' useradmin '), ('etc'), (' other user ')
GO
-- some mock data to obtain a large number of records
insert into dbo.tblUsers (Username)
select top 20000 SUBSTRING(text, 1, 64) from sys.messages
GO
Test
-- this will use the index (index seek)
select * from tblUsers where UsernameTrimmed in (LTRIM(RTRIM('abc')), LTRIM(RTRIM(' useradmin ')));
This allows for faster retrievals at the expense of extra space.
In order to get rid of query construction (and the ugliness of many LTRIMs and RTRIMs), you can push searched users in a table that looks like tblUsers.
create table dbo.searchedUsers
(
Username NVARCHAR(64) NOT NULL,
UsernameTrimmed AS LTRIM(RTRIM(Username)) PERSISTED
)
GO
Push raw values into dbo.searchedUsers.Username column and the query should look like this:
select U.*
from tblUsers AS U
join dbo.searchedUsers AS S ON S.UsernameTrimmed = U.UsernameTrimmed
The big picture
It is way better to properly trim your data in the service layer of your application (C#) so that future clients of your table may rely on decent information. So, trimming should be performed both when inserting information into tblUsers and when searching for users (IN values)

Answer 4

select *
from tblUsers
where RTRIM(LTRIM(Username)) in ('abc','xyz','pqr','mnop');

Answer 5

Answer: SELECT * FROM tblUsers WHERE LTRIM(RTRIM(Username)) in ('abc','xyz','pqr','mnop');
However, please note that if you have functions in your WHERE clause it defeats the purpose of having an indexes on that column and will use a
scan than a seek.
I would propose you clean your data before inserting into tblUsers

Answer 6

I think you can try this:
Just replace the table2 with you table name form where you are getting the username
select * from tblUsers where Username in ((select distinct
STUFF((SELECT distinct ', ' + RTRIM(LTRIM(t1.Username))
from table2 t1
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,2,'') UserName
from table2 t) );

Answer 7

I'd do it in two step:
1) populate a temp table with all your strings with blanks
2) do a select with a subselect
create table a (a char(1))
insert into a values('a')
insert into a values('b')
insert into a values('c')
insert into a values('d')
create table #b (atmp char(5))
insert into #b values ('a ')
insert into #b values (' b')
insert into #b values (' c ')
select * from a where a in (select ltrim(rtrim(atmp)) from #b)