SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 4)
    Identifier k
    Function sum (children 1)
     ExpressionList (children 1)
      Identifier c
    Function uniqMerge (children 1)
     ExpressionList (children 1)
      Identifier un
    Function uniqThetaMerge (children 1)
     ExpressionList (children 1)
      Identifier ut
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier summing_merge_tree_aggregate_function
   ExpressionList (children 1)
    Identifier k
   ExpressionList (children 1)
    OrderByElement (children 1)
     Identifier k