QSqlQuery problem

[MarkoSan]

Hi to all!

Here is the code:

QString queryString("SELECT * from merchandize WHERE GrupaIdentificationNumber=%1;");
    //QString queryString("SELECT * from merchandize WHERE GrupaIdentificationNumber=2;");    // test
    queryString=queryString.arg(groupId);
    qDebug() << "Query: " << queryString;    // debug
 
    QSqlQuery query(queryString);    // sets up query from query string
    removeAllMerchandize();    // removes all items
    m_iImageCounter=0;    // inits counter
    //query.exec(queryString);    // executes query string
    while (query.next())
    {
                 .....
    }

QString queryString("SELECT * from merchandize WHERE GrupaIdentificationNumber=%1;");
    //QString queryString("SELECT * from merchandize WHERE GrupaIdentificationNumber=2;");    // test
    queryString=queryString.arg(groupId);
    qDebug() << "Query: " << queryString;    // debug
    
    QSqlQuery query(queryString);    // sets up query from query string
    removeAllMerchandize();    // removes all items
    m_iImageCounter=0;    // inits counter
    //query.exec(queryString);    // executes query string
    while (query.next())
    {
                 .....
    }

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As you can see, I've debugged created query and it is ok. But why the program flow skips while loop. The database is filled and the application is connected to it as it must be. I thought there is something wrong with query itself, but as I copied quey, which was produces with qDebug() and pasted it into mysql by hand, I got right results. Can someone help me please?