求问 这样的数据库语句对吗,为什么不报错但是显示空!
XinJian::XinJian(QWidget *parent) :
QWidget(parent),
ui(new Ui::XinJian)
{
ui->setupUi(this);
cunarg1 = new QString();
cunarg2 = new QString();
cunarg3 = new QString();
db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName("stu.db");
db.open();
** //将查到的不重复品牌放到comboBox_pingpai上**
QSqlQuery query;
query.exec("select distinct 品牌 from kucun;");
QSqlRecord rec = query.record();
while(query.next())
{
int index_name = rec.indexOf("品牌");
QString data_name = query.value(index_name).toString();
ui->comboBox_pingpai->addItem(data_name);
}
}
**//根据选定的品牌将不重复的类型放到comboBox_leixing上**
void XinJian::on_comboBox_pingpai_activated(const QString &arg1)
{
QSqlQuery query;
query.prepare("select distinct 类型 from kucun where 品牌 =:x");
query.bindValue(":x",arg1);
query.exec();
QSqlRecord rec = query.record();
ui->comboBox_leixing->clear();
while(query.next())
{
int index_name = rec.indexOf("类型");
QString data_01=query.value(index_name).toString();
ui->comboBox_leixing->addItem(data_01);
}
* cunarg1 = ui->comboBox_pingpai->currentText();
}
**//根据选定的品牌 以及类型 将不重复的型号放到comboBox_xinghao上**
void XinJian::on_comboBox_leixing_activated(const QString &arg1)
{
QSqlQuery query;
query.prepare("select distinct 型号 from kucun where 品牌 =:x and 类型 =:y");
query.bindValue(":x",*cunarg1);
query.bindValue(":y",arg1);
query.exec();
QSqlRecord rec = query.record();
ui->comboBox_xinghao->clear();
while(query.next())
{
int index = rec.indexOf("型号");
QString data_02 = query.value(index).toString();
ui->comboBox_xinghao->addItem(data_02);
}
*cunarg2 = ui->comboBox_leixing->currentText();
}
**//根据选定的品牌 类型 以及 型号 将取到的单价放到spinBox上 现在的问题就是spinbox不显示值__**
void XinJian::on_comboBox_xinghao_activated(const QString &arg1)
{
QSqlQuery query;
query.prepare("select from kucun where 品牌=:x and 类型=:y and 型号=:a");
query.bindValue(":x",*cunarg1);
query.bindValue(":y",*cunarg2);
query.bindValue(":a",arg1);
query.exec();
QSqlRecord rec = query.record();
ui->spinBox->clear();
while(query.next())
{
int index = rec.indexOf("单价");
QString danjia = query.value(index).toString();
ui->spinBox->setValue(index);
}
*cunarg3=ui->comboBox_xinghao->currentText();
}
XinJian::~XinJian()
{
db.close();
delete ui;
}