SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t1
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      Subquery (alias t2) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 3)
          ExpressionList (children 2)
           Identifier key
           Function sum (alias val) (children 1)
            ExpressionList (children 1)
             Identifier val
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier t2
          ExpressionList (children 1)
           Identifier key
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier t1.key
        Identifier t2.key
