SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 1)
    Function concat (alias x) (children 1)
     ExpressionList (children 2)
      Identifier func.name
      Identifier comb.name
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.functions (alias func)
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier system.aggregate_function_combinators (alias comb)
     TableJoin (children 1)
      ExpressionList (children 1)
       Identifier name
   Identifier is_aggregate
   Set
