With the following code:

QSqlQuery query("select * from person where ID=101");
query.exec("insert into person values(108, 'Maria2', 'Papadopoulos')");
qDebug()<<query.executedQuery().toAscii();

executedQuery() returns incorrect query since SqlQuery::exec(const QString& query) does not set executedQuery -variable. But calling bool QSqlQuery::exec() sets the executedQuery, and then correct query is returned with QSqlQuery::executedQuery().