How to show the result of multiple selects in QTableView using QSqlQueryModel

Question

I am using the following approach to show the result of a select statement in the QTableView. How should I modify this code to show the result of two or more different select statements in the same QTableView?

QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
QString dbPath = "test1.db";
db.setDatabaseName(dbPath);

QSqlQueryModel *model = new CustomSqlModel();

QSqlQuery* query = new QSqlQuery(db);
query->prepare("SELECT * FROM MyTable");
query->exec();

model->setQuery(*query);
model->setHeaderData(0, Qt::Horizontal, "Col1");
model->setHeaderData(1, Qt::Horizontal, "Col2");
model->setHeaderData(2, Qt::Horizontal, "Col3");

QTableView* tableView = new QTableView();
tableView->setModel(model);

I need to append the data selected from the same table in another database test2.db to the data already shown in the tableView.

Answer 1

To append the result of one query to another, use a compound SELECT statement:

SELECT * FROM MyTable
UNION ALL
SELECT * FROM MyOtherTable

This requires that the subselects have the same number of columns.

If the other table is in another database, you must ATTACH it to the first one:

db.exec("ATTACH '/somewhere/else/test2.db' AS test2");
...
query->prepare("SELECT * FROM MyTable UNION ALL SELECT * FROM test2.MyTable");