第 57 题 (单选题)： Which is the default column or columns for sorting output from compound queries using SET operators such as INTERSECT in a SQL statement.

A. the first NUMBER or VARCHAR2 column in the last select of the compound query. B. the first NUMBER column in the first select of the compound query. C. the first vARCHAR2 column in the first select of the compound query . D. the first column in the first select of the compound query. E. the first column in the last selects of the compound query 显示答案