create table if not exists t_user (
        username text,
        password text
);

bool Foo(const QString &username, const QString &password)
{
    int res = 0;
    sqlite3_stmt *stmt = NULL;
    const char sql[] = "select count(username) from t_user where username = ? and password = ?;";
    res = sqlite3_prepare_v2(db, sql, strlen(sql), &stmt, NULL);//res == SQLITE_OK

    res = sqlite3_bind_text(stmt, 1, username.toUtf8().data(), username.toUtf8().size(), NULL);//res == SQLITE_OK
    res = sqlite3_bind_text(stmt, 2, password.toUtf8().data(), password.toUtf8().size(), NULL);//res == SQLITE_OK

    res = sqlite3_step(stmt);//res == SQLITE_ROW
    res = sqlite3_column_int(stmt, 0);

    sqlite3_finalize(stmt);
    return res > 0;
}