A.DISTINCT BY B.ORDER BY C.GROUP BY D.CRATER BY
A.[姓名]Is Null B.[姓名]Not Is Null C.[姓名]Like Is Null D.[姓名]OR Is Null
A.Select 學(xué)號(hào) from 成績 where 成績<60 B.Select 課程編號(hào) from 成績 where 成績<60 C.Select 學(xué)號(hào) from 成績 where<60 D.Select 課程編號(hào) from 成績 where<60