Returning multiple columns in Neo4jClient Cypher Query - neo4jclient

Question

I am using Azure and finding the performance to be slow. In order to reduce the round trip time, I am clubbing the following queries into one query.
var queryItem = _graphClient
.Cypher
.Start(new
{
n = Node.ByIndexLookup("item_idx", "SKU", sSKU1),
})
.Return<Node<Item>>("n");
somewhere else in the code I have following statements
var queryItem = _graphClient
.Cypher
.Start(new
{
m = Node.ByIndexLookup("item_idx", "SKU", sSKU2),
})
.Return<Node<Item>>("m");
I tried to combine above two queries into a single query like this
var queryItem = _graphClient
.Cypher
.Start(new
{
n = Node.ByIndexLookup("item_idx", "SKU", sSKU1),
m = Node.ByIndexLookup("item_idx", "SKU", sSKU2),
})
.Return<Node<Item>>("n");
I know above is only for single column so I tried using following return statement
.Return((n, m) => new
{
N = n.CollectAs<Node<Item>>(),
M = m.CollectAs<Node<Item>>()
});
but then I have problems with the following statement
Node<Item> item1 = itemQueryResult.First();
It says Error Cannot implicitly convert type 'AnonymousType#1' to 'Neo4jClient.Node.
Can you please suggest a simple syntax or returning multiple columns and a way to extract the first node? TIA.

Answer 1

I think what you're missing here is that the Return statement returns one object per Cypher row.
Your query is returning a table like this:
|-----------------|
| n | m |
|-----------------|
| Node | Node |
|------------------
That's one table, with one row, with two columns.
In this statement, you are returning an anonymous type per Cypher row:
.Return((n, m) => new
{
N = n.CollectAs<Node<Item>>(),
M = m.CollectAs<Node<Item>>()
});
The return type of that method is IEnumerable<AnonymousType>.
You're then trying to get the first row (an anonymous type) and implicitly cast that to Node<Item>, which is not valid.
You should get the row, then get the properties within it.
Some other things to note:
You don't want to use CollectAs in this scenario: that will turn each cell of your table into an array with a single value, which just adds more indirection.
.As<Node<T>>() can be written as .Node<T>()
With that in mind, here's the query you want:
var result = _graphClient
.Cypher
.Start(new
{
n = Node.ByIndexLookup("item_idx", "SKU", sSKU1),
m = Node.ByIndexLookup("item_idx", "SKU", sSKU2),
})
.Return((n, m) => new
{
N = n.Node<Item>(),
M = m.Node<Item>()
})
.Results
.Single();
var n = result.N;
var m = result.M;
Make sense?
PS: I hope you aren't actually clubbing anything. Baby seals don't like that. You are combining queries.