SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function concat (children 1)
     ExpressionList (children 2)
      Function __actionName (children 1)
       ExpressionList (children 2)
        Literal \'aaa\'
        Function toNullable (children 1)
         ExpressionList (children 1)
          Literal \'x\'
      Literal \'1\'
   ExpressionList (children 1)
    Function __actionName (children 1)
     ExpressionList (children 2)
      Literal \'aaa\'
      Literal \'x\'
