The table below is an extract of a larger set of data
In my scenario Column 2 is null when is the "parent" record (Column 1 = AB1 and Column 2 is NULL) and as you can see the following 2 "child" records under Column 2 have AB1 as identifier which matches the AB1 from Column 1, what I want to do is to sum the values on Column 3 when Column 2 has the same identifier (AB1), up to this point the sum = 29 (for this case I can do a SUM and group by AB1). My issue arises when I need to add the value of 10 in Column 3 when column 2 is NULL and Column 1 is AB1 (parent identifier). The common identifier is AB1 but for the parent record the identifier is in Column 1 instead of Column 2. I need a SQL that return a total sum of 39.
