已知有scores表,scoreid为主键,现在表中共有10条记录,其中一条scoreid=21。
创建视图:
create view view_scores
as
select * from scores
执行如下命令:
delete from view_scores where (scoreid = 21)
再执行如下命令:
select * from scores
select * from view_scores
假定上述命令全部执行成功,将各自返回( )( )行记录。
已知有scores表,scoreid为主键,现在表中共有10条记录,其中一条scoreid=21。
创建视图:
create view view_scores
as
select * from scores
执行如下命令:
delete from view_scores where (scoreid = 21)
再执行如下命令:
select * from scores
select * from view_scores
假定上述命令全部执行成功,将各自返回( )( )行记录。