假设有a,b两张表,a表和b表通过name和age字段关联后去更新a表的course字段，并且a表的schooleId为1的更新语句如下
update a inner join b zu on a.name=b.name and a.age=b.age set a.course=b.course where a.schooleId=1; update a inner join b zu on a.name=b.name and a.age=b.age set a.course=b.course where a.schooleId=1;
