Help with dynamic sequel. Return only Distinct Name.

Question

This is simple but how can I return only distinct login name.  Just want to return one set of values.
Please see the desire output and the rule below.  I am using SQL2012.
Thank you for your help in advance.
USE Tempdb;
go
DROP TABLE [dbo].[UserRoleTest];
GO
CREATE TABLE [dbo].[UserRoleTest]
 [LoginId] [varchar](35) NULL,
 [UserName] [varchar](35) NULL,
 [DBRole] [varchar](35) NULL
) ON [PRIMARY]
GO
INSERT INTO dbo.UserRoleTest([LoginId],[UserName],[DBRole])
  VALUES ('[MyDomain\Peter]', 'MyDomain\Peter', '[db_datareader]' ) ;
INSERT INTO dbo.UserRoleTest([LoginId],[UserName],[DBRole])
  VALUES ('[MyDomain\Peter]', 'MyDomain\Peter', '[db_datawriter]' ) ;
INSERT INTO dbo.UserRoleTest([LoginId],[UserName],[DBRole])
  VALUES ('[Home\John]', 'Home\John', '[db_datareader]' ) ;
INSERT INTO dbo.UserRoleTest([LoginId],[UserName],[DBRole])
  VALUES ('User1', 'User1', '[db_datareader]' ) ;
INSERT INTO dbo.UserRoleTest ([LoginId],[UserName],[DBRole])
  VALUES ('User1', 'User1', '[db_datawriter]' ) ;
SELECT *
  FROM [dbo].[UserRoleTest]
go
USE Tempdb;
go
IF OBJECT_ID('dbo.usp_test', 'p') IS NOT NULL
  DROP PROCedure dbo.usp_test
GO
CREATE PROCedure dbo.usp_test
AS
SET NOCOUNT ON;
DECLARE @SQLStr      VARCHAR(8000)
       ,@iCounterId  INT
       ,@LoginId     VARCHAR(35)
       ,@UserName    VARCHAR(35)
       ,@DBRole      VARCHAR(35)
       ,@DBName      VARCHAR(40)
       ,@crlf        CHAR(1) = CHAR(13) + CHAR(10) -- carriage return, new line.
SET @DBName = 'Tempdb'    
--ALTER USER and ALTER ROLE.
DECLARE @t TABLE
  iCounterId   INT  IDENTITY(1,1)  NOT NULL PRIMARY KEY NONCLUSTERED
 ,LoginId      VARCHAR(35)             NULL
 ,UserName     VARCHAR(35)             NULL
 ,DBRole       VARCHAR(35)             NULL
 INSERT @t (LoginId, UserName, DBRole)
 SELECT LoginId, UserName, DBRole
   FROM dbo.UserRoleTest
  --WHERE (DBName = @DBName);
--SELECT * FROM @t
SET @iCounterId = ( SELECT MIN(iCounterId)
                      FROM @t );
   WHILE ( @iCounterId IS NOT NULL )
     BEGIN
       IF ( @iCounterId IS NULL )
         BEGIN
           PRINT 'Exit'
           BREAK
         END
       -- Pick 2 variables.
       SELECT @LoginId = LoginId
             ,@UserName = UserName
             ,@DBRole = DBRole
         FROM @t
        WHERE (iCounterId = @iCounterId )
        --SQL Statement
        --PRINT 'LoginId: ' + @LoginId
        --PRINT 'UserName: ' + @UserName
        --PRINT 'DBRole: ' + @DBRole
         -- This section create users if users do not exist.
         SET @SQLStr = 'USE [' + RTRIM(@DBName) + '];' + @crlf
         SET @SQLStr = @SQLStr + 'IF NOT EXISTS ( SELECT 1 FROM sys.sysusers WHERE [name] = ''' + RTRIM(@UserName) + ''' )' + CHAR(13) +
                          '  BEGIN' +  @crlf + '    CREATE USER ' + @LoginId + ' FOR LOGIN
' + @LoginId + ' WITH DEFAULT_SCHEMA = [' + @UserName + '];' + @crlf +
                          '    ALTER ROLE ' + RTRIM(@DBRole) + ' ADD MEMBER ' + RTRIM(@LoginId) + ';'
+ @crlf + '  END;' + CHAR(13) +
                          'ELSE ' + CHAR(13) + '  BEGIN' + @crlf + '    ALTER USER ' + RTRIM(@LoginId) 
+ ' WITH LOGIN = ' + RTRIM(@LoginId) + ';' + CHAR(13) +
                          '    ALTER ROLE ' + RTRIM(@DBRole) + ' ADD MEMBER ' + RTRIM(@LoginId) + ';'
+ @crlf + '  END;' + @crlf
         PRINT @SQLStr
      SET @iCounterId = ( SELECT MIN(iCounterId)
                            FROM @t
                           WHERE iCounterId > @iCounterId )
   END
GO
EXECute dbo.usp_test
-- Result want:
-- Just return 1 set like below.  Thank you so much.
USE [Tempdb];
IF NOT EXISTS ( SELECT 1 FROM sys.sysusers WHERE [name] = 'MyDomain\Peter' )
 BEGIN
   CREATE USER [MyDomain\Peter] FOR LOGIN [MyDomain\Peter] WITH DEFAULT_SCHEMA = [MyDomain\Peter];
   ALTER ROLE [db_datareader] ADD MEMBER [MyDomain\Peter];
   ALTER ROLE [db_datawriter] ADD MEMBER [MyDomain\Peter];
 END;
 ELSE
  BEGIN
     ALTER USER [MyDomain\Peter] WITH LOGIN = [MyDomain\Peter];
    ALTER ROLE [db_datareader] ADD MEMBER [MyDomain\Peter];
    ALTER ROLE [db_datawriter] ADD MEMBER [MyDomain\Peter];
 END;

Answer 1

Here is an improved version of Prashath's script:
* I use FOR XML PATH which is guaranteed to work to concatenation. The method that Prashanth uses does not have a defined behaviour.
* I'm using quotename through out to delimit all names.
* I did not like that that some names in the table were brackted, but I found a way to neutralise that with parsename. (But that would fail if there is an unquoted name with a dot in it.)
* I introduced the variables @nl and @to make formatting cleaner.
DECLARE @sql nvarchar(MAX) = N'',
        @nl char(2) = char(13) + char(10)
DECLARE @go char(6) = @nl + 'go' + @nl
;WITH cte(UserName, LoginId, DBRole, rn) AS (
   SELECT parsename(UserName, 1), parsename(LoginId, 1), parsename(DBRole, 1),
          ROW_NUMBER() OVER(PARTITION BY UserName, LoginId ORDER BY UserName, LoginId)
   FROM dbo.[UserRoleTest]
SELECT @sql =
   (SELECT CASE WHEN rn = 1 THEN N'IF user_id(' + quotename(UserName, '''') + ') IS NULL ' + @nl +
                    '    CREATE USER '  + quotename(LoginId) + ' FOR LOGIN ' + quotename(LoginId) +
                    ' WITH DEFAULT_SCHEMA = ' + quotename(UserName)
                ELSE 'ALTER USER ' + quotename(LoginId)  + ' WITH LOGIN = ' + quotename(LoginId)
           END  + @go +
           'ALTER ROLE ' + quotename(DBRole) + ' ADD MEMBER ' + quotename(LoginId) + @go
     FROM cte
     ORDER BY rn
     FOR XML PATH(''), TYPE).value('.', 'nvarchar(MAX)')
PRINT @sql;
Erland Sommarskog, SQL Server MVP, [email protected]