SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 5)
   ExpressionList (children 2)
    Identifier a
    Function sum (children 1)
     ExpressionList (children 1)
      Identifier b
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 3)
           Literal UInt64_1 (alias a)
           Literal UInt64_1 (alias b)
           Literal UInt64_0 (alias c)
   ExpressionList (children 1)
    Identifier a
   Identifier c
   Set
