Why doesn't it understand the date type?

Question

SQL

There is a change request in Qt like this:

setquery1->setQuery("UPDATE ships SET n_sudopot = '"+N_sp+"', data_prib_p_nazn = '"+data_prib.toString()+"', "
                               "dispetcher = '"+dispetcher+"' WHERE id="+indid+";");

The request itself is not executed.
data_prib_p_naznin MySQL it is of type DATE;
data_prib
tried to use in two types:

QDate data_vih = ui->dateEdit->date();               
QString data_vih = ui->dateEdit->date().toString();

If you remove the date from the request, then everything will work.
Which type would be used correctly?

Answer 1

According to the specification, the DATE type in SQL looks like this: yyyy-mm-dd. We go into the Qt documentation and see one of the signatures ( doc.qt.io/qt-5/qdate.html#toString-1 ):
QString QDate::toString(Qt::DateFormat format = Qt::TextDate) const
Ie . you need it like this: ui->dateEdit->date().toString(Qt::ISODate)

Answer 2

What will return 2018-08-18 - that will do

Answer 3

Try like this: '20180814'