--results:
Status cnv                            id          val     id          val
------ ------------------------------ ----------- ------- ----------- -------
Pass   Hello                          1           Hello   1           Hello
Pass   abc123                         2           abc123  2           abc123
Fail   ???                            3           太平市     3           太平市
Fail   abc?123                        4           abc太123 4           abc太123

SELECT 1 as id,N'Hello' As val
INTo #TMP UNION ALL
SELECT 2 as id,N'abc123' UNION ALL
SELECT 3 as id,N'太平市'  UNION ALL
SELECT 4 as id,N'abc太123'

SELECT 
  CASE 
    WHEN t1.val = CONVERT(varchar,t2.val) 
    THEN 'Pass' 
    ELSE 'Fail'
  END As Status,
  CONVERT(varchar,t2.val) As cnv,* 
FROM #TMP t1
  LEFT OUTER JOIN #TMP t2
  ON t1.Id = t2.ID