SQL query not working

ronyNS

QSqlQuery a;
    QString b;
    a.exec("Select Stock From Manufacturer_stock Where Product=Parle");
    if (a.next()) {

            b = a.value(0).toString();
            ui->label_2->setText(b);
           }

This code does nothing. What is wrong?

mrjj

Hi
The syntax is not valid i think
a.exec("Select Stock From Manufacturer_stock Where Product='Parle' ");
( add single quotes around text values )

If you are using SQLite then
http://sqlitebrowser.org/
Is nice tools as you can test your SQL there and easy work with the database.

ronyNS

I am using Access and the code is swill not working
i tried with quotes
i dont know whats wrong. All other queries are working fine.

mrjj

@ronyNS
Well are you sure it will get any hits then?
and Column is called Stock ?

ronyNS

Yes i cross checked everything . Everything is perfect

mrjj

@ronyNS

You can try
a.exec("Select Stock From Manufacturer_stock Where Product like 'P%' ");

And see if it matches Parla.

Else i am out of guesses. Did Not use Access since 1997 :)

p3c0

lastError should give you the exact cause of error.
Additionally check if the database is opened using isOpen or errors if any.

mjsurette

I believe that the SQL standard requires a trailing semicolon (;) but some databases/drivers choke on it. Try

a.exec("Select Stock From Manufacturer_stock Where Product='Parle';");

Mike

Pradeep Kumar

HI

Can u try with this, hope this works for you.

QSqlQuery query;
query.prepare("Select Stock From Manufacturer_stock Where Product='Parle'; ");
query.exec();
while(query.next())
{
    QString firstValue = query.value(0).toString();
    qDebug() << "first value :" << firstValue  << endl;

    QString secondValue = query.value(1).toString();
    qDebug() << "second value :" << secondValue  << endl;
 }

and provide debug statements,
As mentioned by @p3c0 check whether the dB is opened.

Tschikkn

Hi!

You should get the error-message as already mentioned above:

QSqlQuery a;
if( !a.exec("Select Stock From Manufacturer_stock Where Product='Parle';") ) {
    qDebug() << "Error:" << a.lastError().text();
    }