MySQL 오류 관련하여 질문 있습니다.

개발환경 : Delphi XE4
DB : MySQL 5.6

DBExpress 사용하여 DB 접속하고 있는데...

아래와 같은 오류가 발생합니다.

dbExpress driver does not support the TDBXTypes.UNKNOWN data type.  Vendor error message: 

쿼리는 아래와 같은데...

SELECT ROWNUM                                                                                      
     , INSERT_TIME                                                                                 
     , B                                                                                   
     , C                                                                                  
     , D                                                                                 
     , E                                                                                
     , F                                                                                  
  FROM  (                                                                                          
         SELECT  A.*, @RNUM:=@RNUM+1  AS ROWNUM                                                    
           FROM  ( SELECT INSERT_TIME, B, C, D, E, F
                     FROM TAB                                              
                    ORDER BY INSERT_TIME DESC )  A                                                 
              ,  ( SELECT @RNUM:=0 ) B                                                             
        ) A                                                                                        
WHERE ROWNUM <= 100                                                                               
ORDER BY ROWNUM DESC 

위 쿼리에서 @RNUM:=@RNUM+1, @RNUM:=0 을 빼고 실행하면 정상적으로 작동이 됩니다.

해결방법 알고 계신 분은 답변 부탁 드립니다.

수고 하십시요.