SQL Server HASHBYTES conversion inconsistency?

Question

When I execute this hardcoded, I get the correct result:

Declare @result nvarchar(32)

Set @result = convert(varchar(32), hashbytes('MD5', '1' + 'One' + 'Two' + 'Three'), 2)

select @result

Result: 4173AB4C6EE66BC1FF7B7E5D44A872CA (correct)

But when I call/execute this stored procedure, giving it the same parameters, it's a different result

ALTER Procedure [db_owner].[CheckTheTransaction]
    @DataID nvarchar(50),
    @Data1 nvarchar(50),
    @Data2 nvarchar(50),
    @Data3 nvarchar(50)
as
    Declare @result nvarchar(32)
    Set @result = convert(varchar(32), hashbytes('MD5', @DataID + @Data1 + @Data2 + @Data3), 2)

    Select @result

My execution:

DECLARE @result int

EXEC    @result = [db_owner].[CheckTheTransaction]
        @DataID = '1',
        @Data1 = 'One',
        @Data2 = 'Two',
        @Data3 = 'Three'

SELECT  'Result' = @result

GO

Result: 5BD42777932EE959AD5A4C9FEE142F00 (wrong)

Where did I go wrong?

Answer 1

My team member asked a similar question and accepted the answer that solved it. Comparing a C# generated Checksum with a SQL Server one

Answer 2

That is a data type issue. You will see it match by changing the T-SQ script to followings.

Declare @result nvarchar(32)

Set @result = convert(varchar(32), hashbytes('MD5', N'1' + N'One' + N'Two' + N'Three'), 2)

select @result

Answer 3

Change all nvarchar datatype as varchar

ALTER Procedure [db_owner].[CheckTheTransaction]
@DataID varchar(50),
@Data1 varchar(50),
@Data2 varchar(50),
@Data3 varchar(50)
as
  Declare @result nvarchar(32)
  Set @result = convert(varchar(32), hashbytes('MD5', @DataID + @Data1 +         
  @Data2 + @Data3), 2)

Select @result