SQLServer 2005 does not do the right thing - sql-server

Question

I have a problem when trying with Like statement like this:
First I have the data sheet:
When I execute the Sql command it does not do what I want.
My syntax:
select * from tbUsers where nUserID like N'%p%';
It does not show any results. Although I know that 'Finds any values ​​that have' p 'in any position'
result picture:
my code to create table:
Create table tbUsers(
iIDUser int identity(1,1) not null primary key,
nUserID nvarchar(50) null,
nPassWord nvarchar(50) null,
dDate datetime null,
nName nvarchar(50) null
)
INSERT INTO tbUsers(nUserID,nPassword,nName) VALUES('phuc','123456', 'Phuc Nguyen')
INSERT INTO tbUsers(nUserID,nPassword) VALUES('ngocanh','123456')
INSERT INTO tbUsers(nUserID,nPassword) VALUES('long','123456')
INSERT INTO tbUsers(nUserID,nPassword) VALUES('long%ngocanh','123456')
INSERT INTO tbUsers(nUserID,nPassword) VALUES('phuc nguyen','123456')
Please help me. Thank you.

Answer 1

Hi your problem can be your collation if you need the Vietnamese collation for any reason you can alter your query to use the collation in your query like this one:
select *
from tbUsers
where nUserID collate SQL_Latin1_General_CP1_CI_AS like N'%p%';
If not my recommendation is to re-create the database using the collation SQL_Latin1_General_CP1_CI_AS since this query will be slow.
Also take in consideration if you have an index in the user column using double %% this will not let your index to be used. If you use only one % the index will be activated. Take a look of the execution plan to review this.
If want to stay with the Vietnamese collation maybe change the collation to the columns you need for this type of functionality. This will help you with the performance.
To change the collation of a column use
ALTER TABLE MyTable ALTER COLUMN Column1 [TYPE] COLLATE [NewCollation]
You can take a look to this question for more details
How to set collation of a column with SQL?

Answer 2

Since you are using Vietnamese collation you are not getting back the rows. You can specify the collation in your query quite easily though and it will return the rows you are looking for.
select *
from tbUsers
where nUserID collate SQL_Latin1_General_CP1_CI_AS like N'%p%';