Neo4j: Handling SUM's Scientific Notation
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Join For FreeIn some of the recent work I’ve been doing with neo4j the queries I’ve written have been summing up the values from multiple nodes and after a certain number is reached the value returned used scientific notation.
For example, in a cypher query like this:
START category = node:categories('category_id:1')
MATCH p = category-[:has_child*1..5]->subCategory-[:has_product]->product-[:sold]->sales
RETURN EXTRACT(n in NODES(p) : n.category_id?),subCategory.category_id, SUM(sales.sales)
I might get a result set like this:
+------------------------------------------------------------------------------------------------+ | EXTRACT(n in NODES(p) : n.category_id?) | subCategory.category_id | SUM(sales.sales) | +------------------------------------------------------------------------------------------------+ | ["246","254","255","3279",<null>,<null>] | "3279" | 3.07213e07 | | ["246","3649","3650","4362",<null>,<null>] | "4362" | 1.023412e06 | | ["246","287","291","308",<null>,<null>] | "308" | 504712.5999448135 | +------------------------------------------------------------------------------------------------+
I wanted to be able to add the first two rows together but still have
them return separately which meant I needed to convert the values into
decimal notation in order to do so.
I came across a Stack Overflow thread explaining how to do it in Ruby:
> "%f" % "3.07213e07" => "30721300.000000"
or
> "3.07213e07".to_f => 30721300.0
If we want to do the same thing in Java it’d read like this:
double d = Double.parseDouble("3.07213e07"); NumberFormat formatter = new DecimalFormat("###.#####"); String f = formatter.format(d); System.out.println(f); // returns 30721300
I couldn’t see a way to make the SUM function return in decimal notation but it’d be neat if there was a way to.
For now we have to apply some formatting on the result if we want to do any calculations with it.
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