SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function toUInt32OrDefault (children 1)
     ExpressionList (children 2)
      Function toNullable (children 1)
       ExpressionList (children 1)
        Function toUInt32 (children 1)
         ExpressionList (children 1)
          Literal UInt64_1
      Function toNullable (children 1)
       ExpressionList (children 1)
        Function toUInt32 (children 1)
         ExpressionList (children 1)
          Literal UInt64_2
   Set