用like 和 case when

用MySQL測試OK

表格

CREATE TABLE IF NOT EXISTS `docs` (
  `id` int(6) unsigned NOT NULL,
  `fileName` varchar(200) NOT NULL,
  PRIMARY KEY (`id`)
) DEFAULT CHARSET=utf8;
INSERT INTO `docs` (`id`, `fileName`) VALUES
  ('1', '111-1.pdf'),
  ('2', '111-2.pdf'),
  ('3', '99-1.pdf'),
  ('4', '99-2.pdf');

Select

select 
CASE 
  WHEN a.fileName LIKE '%-1%' THEN 'A檔案'
  WHEN a.fileName LIKE '%-2%' THEN 'B檔案'
ELSE '' END AS FileType
  from `docs` as a;

簡單版(假設你的檔案只有PDF， *1.pdf 為A檔，*2.pdf 為b檔，upper硬轉大寫 )

SELECT CASE WHEN UPPER(RIGHT(FILENAME,5))='2.PDF' THEN 'B' ELSE 'A' END FILETYPE 
FROM YOURTABLE 
WHERE .......

畫蛇添足版(取檔名 . 的左邊的所有文字，再取最右邊那個字)

SELECT CASE WHEN RIGHT(LEFT(FILENAME,CHARINDEX('.',FILENAME)-1),1)='1' THEN 'A' ELSE 'B' END FILETYPE 
FROM YOURTABLE 
WHERE .....