delete與select

多表連接實現刪除：

delete from sc

from sc join student on sc.sno = student.sno

where grade <60 and sdept = '計算機系'

此處中的delete操作不可寫成與select操作一樣

select * from sc,student                                    正確

where sc.sno=student.sno and grade <60 and sdept='計算機系'

而

delete from sc, student                                     錯誤

 where sc.sno = student.sno and grade <60 and sdept = '計算機系'