数据库中有3个表:teacher,student,tea—stu,teacher表teaId,name,age...答:1.Select b.teald,a.name,count(b.stuld) as 所带学生人数 from teacher a,tea-stu b where a.teald=b.teald group by b.teald,a.name 2.select from student a,teacher b,tea-stu c where a.stuld=c.stuld and b.teald=c.teald and a.age>12 and b.age<40 ...