310104是上海市徐汇区的身份证号前6位。上海身份证号前两位是以31开头的,具体到区县的代码如下:
3101:上海市市辖区,310101:上海市黄浦区,310102:上海市南市区,310103:上海市卢湾区310104:上海市徐汇区,310105:上海市长宁区,310106:上海市静安区,310107:上海市普陀区,310108:上海市闸北区,310109:上海市虹口区,310110:上海市扬浦区,310112:上海市闵行区310113:上海市宝山区,310114:上海市嘉定区,310115:上海市浦东新区,3102:上海市市辖县,310225:上海市南汇县,310226:上海市奉贤县,310227:上海市松江县,310228:上海市金山县,310229:上海市青浦县,310230:上海市崇明县。