gorm更新字段值+1或-1 func (xy *XJGYTopic) AdUpdateSignUpNum(id int64)bool{ifxy.ID <=0{returnfalse}iferr := Db.Model(xy).Where("id = ?", id).Update("sign_up_num", gorm.Expr("sign_up_num+ ?",1)).Error; err !=nil {returnfalse}returntrue}...