Hi,
I have found the cause:

my SQL :

SELECT ..... INNER JOIN ... WHERE... ;
UNION ALL ;
SELECT ..... INNER JOIN ... WHERE... ;
ORDER BY 1,2,3,4      && This cause error

This SQL works fine if I

USE myView AGAIN SHARED IN 0
REQUERY()

However, it will cause error if

USE myView AGAIN SHARED IN 0 NODATA
REQUERY()           && ERROR orccured 

My current workaround is remove ORDER BY clause from this sql, and create another view just to ORDER it.

Any better way?

Thank you