SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function if (children 1)
     ExpressionList (children 3)
      Function greater (children 1)
       ExpressionList (children 2)
        Function materialize (children 1)
         ExpressionList (children 1)
          Literal UInt64_1
        Literal UInt64_0
      Function materialize (children 1)
       ExpressionList (children 1)
        Function toInt32 (children 1)
         ExpressionList (children 1)
          Literal UInt64_1
      Function CAST (children 1)
       ExpressionList (children 2)
        Literal NULL
        Literal \'Nullable(Int64)\'
