Как оформить форму в Qt designer для ввода select

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QCheckBox, QComboBox
from PyQt5.QtWidgets import QGroupBox, QTableView, QVBoxLayout, QGridLayout
from PyQt5.QtSql     import QSqlDatabase, QSqlQuery, QSqlQueryModel
from PyQt5.QtCore    import Qt
 
class Window(QWidget):
  def __init__(self):
    super().__init__(None)
    self.box = QVBoxLayout()
    self.selector = QComboBox()
    self.view = QTableView()
    self.view.setModel(QSqlQueryModel())
    group = QGroupBox()
    group.setLayout(self.box)
    tables = QSqlQueryModel()
    tables.setQuery("SELECT name FROM PRAGMA_TABLE_LIST();")
    self.selector.currentIndexChanged.connect(self.updateBox)
    self.selector.setModel(tables)
    l = QGridLayout()
    l.addWidget(self.selector, 0, 0)
    l.addWidget(group, 1, 0)
    l.addWidget(self.view, 0, 1, 2, 1)
    self.setLayout(l)
 
  def updateBox(self):
    while True:
      child = self.box.takeAt(0)
      if child is None:
        break
      child.widget().deleteLater()
      #del child
    query = QSqlQuery()
    query.prepare("SELECT name FROM PRAGMA_TABLE_INFO(:table);")
    query.bindValue(":table", self.selector.currentText())
    query.exec_()
    while query.next():
      check = QCheckBox(query.record().value(0))
      check.stateChanged.connect(self.updateView)
      self.box.addWidget(check)
    self.updateView()
 
  def updateView(self):
    fields = []
    for i in range(self.box.count()):
      w = self.box.itemAt(i).widget()
      if w.checkState() == Qt.Checked:
        fields.append(w.text())
    if len(fields)>0:
      #тут надо както через bindValue
      self.view.model().setQuery(
        "SELECT " +
        ", ".join(fields) +
        " FROM " + self.selector.currentText() +
        ";")
    else:
      self.view.model().clear()
 
 
app = QApplication(sys.argv)
db = QSqlDatabase.addDatabase("QSQLITE")
db.setDatabaseName(":memory:")
db.open()
query = QSqlQuery()
query.exec_("PRAGMA foreign_keys = ON;")
query.exec_("CREATE TABLE countries (id INTEGER PRIMARY KEY, name TEXT);")
query.exec_("CREATE TABLE cities (id INTEGER PRIMARY KEY, name TEXT, country INT,"
            "FOREIGN KEY(country) REFERENCES countries(id));");
query.exec_("CREATE TABLE streets (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, city INT,"
            "FOREIGN KEY(city) REFERENCES cities(id));")
query.exec_("INSERT INTO countries (id, name) VALUES (0, 'USA');")
query.exec_("INSERT INTO countries (id, name) VALUES (1, 'Canada');")
query.exec_("INSERT INTO cities (id, name, country) VALUES (0, 'New York', 0);")
query.exec_("INSERT INTO cities (id, name, country) VALUES (1, 'Toronto', 1);")
query.exec_("INSERT INTO cities (id, name, country) VALUES (2, 'Ottawa', 1);")
query.exec_("INSERT INTO streets (name, city) VALUES ('Wall Street', 0);")
query.exec_("INSERT INTO streets (name, city) VALUES ('Seventh Avenue', 0);")
query.exec_("INSERT INTO streets (name, city) VALUES ('Bay Street', 1);")
query.exec_("INSERT INTO streets (name, city) VALUES ('Parliament Street', 1);")
query.exec_("INSERT INTO streets (name, city) VALUES ('Elgin Street', 2);")
query.exec_("INSERT INTO streets (name, city) VALUES ('Bank Street', 2);")
query.exec_("INSERT INTO streets (name, city) VALUES ('Somerset Street', 2);")
query.exec_("INSERT INTO streets (name, city) VALUES ('Preston Street', 2);")
window = Window()
window.show()
sys.exit(app.exec_())