Behavior of Varchar with spaces at the end When I use a Varchar with spaces it ignores the spaces at the end.

ex: 

declare @X varchar(50)


This...

set  @X= 'John'


...is the same as...

set @X= 'John           '


It considers these to be equal.  How can I cause the system to recognize these as different?
Everything is just according the ANSI standard:

Trailing blanks explained:


  SQL Server follows the ANSI/ISO SQL-92 specification (Section 8.2,
  , General rules #3) on how to compare strings
  with spaces. The ANSI standard requires padding for the character
  strings used in comparisons so that their lengths match before
  comparing them. The padding directly affects the semantics of WHERE
  and HAVING clause predicates and other Transact-SQL string
  comparisons. For example, Transact-SQL considers the strings 'abc' and
  'abc ' to be equivalent for most comparison operations.
  
  The only exception to this rule is the LIKE predicate. When the right
  side of a LIKE predicate expression features a value with a trailing
  space, SQL Server does not pad the two values to the same length
  before the comparison occurs. Because the purpose of the LIKE
  predicate, by definition, is to facilitate pattern searches rather
  than simple string equality tests, this does not violate the section
  of the ANSI SQL-92 specification mentioned earlier.


Here's a well known example of all the cases mentioned above:

DECLARE @a VARCHAR(10)
DECLARE @b varchar(10)

SET @a = '1'
SET @b = '1 ' --with trailing blank

SELECT 1
WHERE 
    @a = @b 
AND @a NOT LIKE @b
AND @b LIKE @a


Here's some more detail about trailing blanks and the LIKE clause.

BUT if you want to differ them - you may decide to use DATALENGTH function instead of LEN, because

SELECT 1 WHERE LEN('John ') = LEN('John')


will put you 1 instead of

SELECT 1 WHERE DATALENGTH('John ') = DATALENGTH('John')


The solution is


to use DATALENGTH function to differ between strings
to cast the string into NVARCHAR type - may be better declare this type to parameter of SP