判断数据库中某一行是否已存在

int idExit=0;//0不存在，1存在

QString equipmentId;

QSqlQuery query(plusFSdb);

        QString sql="select b.equipid equipid from fiverule b";

 

        if(!query.exec(sql))

 

        {

 

            QMessageBox::warning(0,"err1",query.lastError().text());

 

        }

 

        while(query.next()){

            QString equipid= query.value(0).toString();

            if(equipid!=equipmentId){

                continue;

            }else if(equipid==equipmentId){

                idExit=1;

            }

        }