第 57 题 (多选题)： Which two statements are true about the DUAL table.

A. It can display multiple rows and columns. B. It can be accessed only by the sys user. C. It can display multiple rows but only a single column. D. It can be used to display only constants or pseudo columns. E. It can be accessed by any user who has the SELECT privilege in any schema. F. It consists of a single row and single column of VARCHAR2 data type 显示答案