SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function if (children 1)
     ExpressionList (children 3)
      Function less (children 1)
       ExpressionList (children 2)
        Identifier number
        Literal UInt64_0
      Function toFixedString (children 1)
       ExpressionList (children 2)
        Function materialize (children 1)
         ExpressionList (children 1)
          Literal \'123\'
        Literal UInt64_2
      Literal NULL
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Function numbers (children 1)
       ExpressionList (children 1)
        Literal UInt64_2
