Suppose there's a following table Table1, describing parent-child relationship and metric: Parent | Child | Metric (of a child) ------------------------------------ name0 | name1 | a name0 | name2 | b name1 | name3 | c name2 | name4 | d name2 | name5 | e name3 | name6 | f Characteristics: 1) Child always has 1 and only 1 parent; 2) Parent can have multiple children (name2 has name4 and name5 as children); 3) Number of levels in this "hierarchy" and number of children for any given parent are arbitrary and do not depend on each other; I need SQL request that will return result set with each name and a sum of metric of all its descendants down to the bottom level plus itself, so for this example table the result would be (look carefully at name1): Name | Metric ------------------ name1 | a + c + f name2 | b + d + e name3 | c + f name4 | d name5 | e name6 | f (name0 is irrelevant and can be excluded). It should be ANSI or Teradata SQL. I got as far as a recursive query that can return a SUM (metric) of all descendants of a given name: WITH RECURSIVE temp_table (Child, metric) AS ( SELECT root.Child, root.metric FROM table1 root WHERE root.Child = 'name1' UNION ALL SELECT indirect.Child, indirect.metric FROM temp_table direct, table1 indirect WHERE direct.Child = indirect.Parent) SELECT SUM(metric) FROM temp_table; Is there a way to turn this query into a function that takes name as an argument and returns this sum, so it can be called like this? SELECT Sum_Of_Descendants (Child) FROM Table1; Any suggestions about how to approach this from a different angle would be appreciated as well, because even if the above way is implementable, it will be of poor performance - there would be a lot of iterations of reading metrics (value f would be read 3 times in this example). Ideally, the query should read a metric of each name only once.