单项选择题
A.InnoDB效率高B.MyISAM用得多C.InnoDB用得多D.MyISAM不支持事务
A.alter table emp delete column addcolumn;B.alter table emp modify column addcolumn char(10);C.alter table emp change addcolumn addcolumn int;D.alter table emp add column addcolumn int;
A.select version()B.select versionC.show version()D.show version