QLineEdit and select

I'm using this code

Code:

---

QSqlQuery query_p_total;
 
		query_p_total.prepare("SELECT :x * :y");
 
		query_p_total.bindValue(":x", ui.peso_por_peca_label->text() );
		query_p_total.bindValue(":y", ui.n_pecas_final_lineEdit->text() );
 
		if (!query_p_total.exec()){
			QMessageBox::critical(0, tr("Error"), 
			QString("There is an error with query.exec()!"));
		}else{
			while (query_p_total.next()) {
			ui.peso_total_final_label->setText(query_p_total.value(0).toString());	
			}
		}

---

ui.peso_por_peca_label->text() ) has value 20.16 and ui.n_pecas_final_lineEdit->text() has value 6, then ui.peso_total_final_label should show me 120.96, but it is showing me 121. When I try to select 20.16 * 6 in the MYSQL console I get the right result, so I think there is something with QLineEdit, but what could it be? Or what else could it be?

Renan

What does query_p_total.value(0).toDouble() return?

returns 121

Renan

And "qDebug() << query_p_total.value(0)"?

this is the return:

QVariant(double, 121)

In that case that is what the database returns.

the hole code:

Code:

---

void testeMYSQL2::on_gerar_pushButton_clicked()
{
	QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
        db.setHostName(ui.hostname_lineEdit->text());
        db.setDatabaseName(ui.database_lineEdit->text());
        db.setUserName(ui.username_lineEdit->text());
        db.setPassword(ui.password_lineEdit->text());
	db.open();
	if (!db.open()){
		QMessageBox::critical(0, tr("Error"), 
		QString("The error:\n%1").arg(db.lastError().text())); 
	}
	else{
		QSqlQuery query;
 
		if (!query.exec("select Mantas.Tipo, Mantas.Espessura, Mantas.Compr_Final, Mantas.Larg_Final,"
		"Mantas.Dens, Mantas.Qtd_Pecas_Final from Mantas where Mantas.ID_Prod = 1010130030000")){
			QMessageBox::critical(0, tr("Error"), 
			QString("There is an error with query.exec()!"));
		}else{
			while (query.next()) {
			ui.prod_label->setText(query.value(0).toString());
			ui.espessura_label->setText(query.value(1).toString() + "MM");
			ui.compr_final_lineEdit->setText(query.value(2).toString());
			ui.larg_final_lineEdit->setText(query.value(3).toString());
			ui.dens_lineEdit->setText(query.value(4).toString());
			ui.n_pecas_final_lineEdit->setText(query.value(5).toString());
			}
		}
		QSqlQuery query_p;
 
//		query_p.prepare(QString("select (%1*%2*%3*%4)/1000000").arg(
//				ui.compr_final_lineEdit->text()).arg(
//						ui.larg_final_lineEdit->text()).arg(ui.espessura_label->text()).arg(ui.dens_lineEdit->text()));
 
		query_p.prepare("SELECT (( :a * :b * :c * :d)/1000000)*1");
 
		query_p.bindValue(":a", ui.compr_final_lineEdit->text() );
		query_p.bindValue(":b", ui.larg_final_lineEdit->text() );
 		query_p.bindValue(":c", ui.espessura_label->text() );
 		query_p.bindValue(":d", ui.dens_lineEdit->text() );
 
		if (!query_p.exec()){
			QMessageBox::critical(0, tr("Error"), 
			QString("There is an error with query.exec()!"));
		}else{
			while (query_p.next()) {
			ui.peso_por_peca_label->setText(query_p.value(0).toString());
			qDebug() << query_p.value(0);
			}
		}
		QSqlQuery query_p_total;
 
		query_p_total.prepare("SELECT :x * :y");
 
		query_p_total.bindValue(":x", ui.peso_por_peca_label->text() );
		query_p_total.bindValue(":y", ui.n_pecas_final_lineEdit->text() );
 
		if (!query_p_total.exec()){
			QMessageBox::critical(0, tr("Error"), 
			QString("There is an error with query.exec()!"));
		}else{
			while (query_p_total.next()) {
			ui.peso_total_final_label->setText(query_p_total.value(0).toString());	
//			qDebug() << query_p_total.value(0).toDouble();
			qDebug() << query_p_total.value(0);
			}
		}
 
	}
	db.close();
}

---

and this is my table:

Code:

---

create table `Mantas` (
 
	`ID_Prod` Decimal (14),
 
	`Tipo` varchar (30),
 
	`Espessura` double ,
 
	`Dens` float ,
 
	`Compr_Inicial` double ,
 
	`Larg_Inicial` double ,
 
	`Qtd_Pecas_Inicial` double ,
 
	`Qtd_Pastas` double ,
 
	`Pastas_Por_Peca` double ,
 
	`Peso_Pasta` float ,
 
	`Peso_Total_Inicial` float ,
 
	`Qtd_Pastas_Capinha` double ,
 
	`Peso_Pasta_Capinha` float ,
 
	`Compr_Final` double ,
 
	`Larg_Final` double ,
 
	`Peso_Por_Peca` float ,
 
	`Peso_Total_Final` float ,
 
	`Qtd_Pecas_Final` double ,
 
	`Quebra` float ,
 
	`Encolh` float 
 
); 
 
insert into `Mantas` (`ID_Prod`, `Tipo`, `Espessura`, `Dens`, `Compr_Inicial`, `Larg_Inicial`, `Qtd_Pecas_Inicial`, `Qtd_Pastas`, 
   `Pastas_Por_Peca`, `Peso_Pasta`, `Peso_Total_Inicial`, `Qtd_Pastas_Capinha`, `Peso_Pasta_Capinha`, `Compr_Final`, `Larg_Final`, 
   `Peso_Por_Peca`, `Peso_Total_Final`, `Qtd_Pecas_Final`, `Quebra`, `Encolh`)
values('1010130030000','ENBCO','3','0.30','20000','1900','6','0','0',
   '5.30',NULL,NULL,'4.60','14000','1600','0.00','0.00','6','0.20','0.30');

---

those are qDebug return in order:

QVariant(double, 20.16)
QVariant(double, 121)

why the second results 121 and the first 20.16 ?

What happens if you use this instead?

Code:

---

double total = query_p_total.value(0).toDouble();
ui.peso_total_final_label->setText( QString::number( total, 'f', 2 ) );

---

Thanks jacek!

That solves my problem.

I have done another thing, but it solves half of my problem ( Now there are too much decimals). I'm going to use your solution. If someone want's here is the code:

Code:

---

QSqlQuery query_p_total;
 
		query_p_total.prepare("SELECT :x * :y");
 
		query_p_total.bindValue(":x", ui.peso_por_peca_label->text().toFloat() );
		query_p_total.bindValue(":y", ui.n_pecas_final_lineEdit->text().toFloat() );
 
		if (!query_p_total.exec()){
			QMessageBox::critical(0, tr("Error"), 
			QString("There is an error with query.exec()!\n%1").arg(query_p_total.lastError().text()));
		}else{
			while (query_p_total.next()) {
			ui.peso_total_final_label->setText(query_p_total.value(0).toString());	
			}
		}

---