SQL数据库试题求解答:--- create table students(st_id varchar(20),st_name varchar(50),sex varchar(10))insert into students(st_id,st_name,sex)select 'st001','张杰', '男' union all select 'st002', '公孙燕飞' ,'男' union all select 'st003', '王楠', '女' union all select 'st004'...