Sum columns with null values in oracle

Question

I want to add two numbers together but when one of those numbers is null then the result is null. Is there a way around this. I could simply do it in the code but I would

Answer 1

In some cases, nvl(sum(column_name),0) is also required. You may want to consider your scenarios.

For example, I am trying to fetch the sum of a particular column, from a particular table based on certain conditions. Based on the conditions,

1. one or more rows exist in the table. In this case I want the sum.
2. rows do not exist. In this case I want 0.

If you use sum(nvl(column_name,0)) here, it would give you null. What you might want is nvl(sum(column_name),0).

This may be required especially when you are passing this result to, say, java, have the datatype as number there because then this will not require special null handling.

Answer 2

select type, craft, sum(NVL(regular, 0) + NVL(overtime, 0)) as total_hours
from hours_t
group by type, craft
order by type, craft

Answer 3

The other answers regarding the use of nvl() are correct however none seem to address a more salient point:

Should you even have NULLs in this column?

Do they have a meaning other than 0?

This seems like a case where you should have a NOT NULL DEFAULT 0 on th ecolumn