Find Nodes

Overview

The find().nodes() statement retrieves nodes from the current graphset that meet the given conditions.

Syntax

Syntax
find().nodes(<filter?>)

• Statement alias: Type NODE; default is nodes
• Methods:

Example Graph

To create the graph, execute the following UQL queries sequentially in an empty graphset:

UQL
create().node_schema("User").node_schema("Club").edge_schema("Follows").edge_schema("Joins")
create().node_property(@User, "name").node_property(@Club, "name").edge_property(@Follows, "time", datetime).edge_property(@Joins, "memberNo", uint32).edge_property(@Joins, "time", datetime)
insert().into(@User).nodes([{_id:"U01", name:"Rowlock"},{_id:"U02", name:"Brainy"},{_id:"U03", name:"purplechalk"},{_id:"U04", name:"mochaeach"},{_id:"U05", name:"lionbower"}])
insert().into(@Club).nodes([{_id:"C01", name:"Rowlock Tennis"},{_id:"C02", name:"Super Yacht"}])
insert().into(@Follows).edges([{_from:"U01", _to:"U02", time:"2024-1-5"},{_from:"U02", _to:"U03", time:"2024-2-1"},{_from:"U04", _to:"U02", time:"2024-2-10"},{_from:"U03", _to:"U05", time:"2024-5-3"}])
insert().into(@Joins).edges([{_from:"U02", _to:"C01", memberNo:1, time:"2023-12-14"},{_from:"U05", _to:"C01", memberNo:2, time:"2024-2-25"},{_from:"U04", _to:"C02", memberNo:9, time:"2024-6-15"}])

Finding All Nodes

To retrieve all nodes:

UQL
find().nodes() as n
return n{*}

Result: n

Finding Nodes with Schemas

To retrieve nodes belonging to the schema Club:

UQL
find().nodes({@Club}) as n
return n{*}

Result: n

To retrieve nodes belonging to the schema Club or User:

UQL
find().nodes({@Club || @User}) as n
return n{*}

Result: n

Finding Nodes with Properties

In filters, properties can be used with their schema or independently. When used independently, they apply to all nodes with that property, regardless of schema. Specifically, system properties _id and _uuid cannot be used with a schema (e.g., @User._id) because they are unique identifiers.

To retrieve @User nodes where name is "Rowlock":

UQL
find().nodes({@User.name == "Rowlock"}) as n
return n._id

Result:

To retrieve nodes where name contains "Rowlock":

UQL
find().nodes({name contains "Rowlock"}) as n
return n._id

Result:

To retrieve nodes where _id is "U01" or "U02":

UQL
find().nodes({_id in ["U01", "U02"]}) as n
return n{*}

Result: n

Using Default Alias

You can use the default alias nodes for the find().nodes() statement without explicitly declaring it.

To retrieve all nodes and return their name (with schema and system properties returned by default):

UQL
find().nodes()
return nodes{name}

Result: nodes

Limiting the Number of Nodes

You can use the LIMIT statememt immediately after the find().nodes() statement to restrict the number of nodes passed to subsequent statements.

To retrieve any 3 @User nodes:

UQL
find().nodes({@User}) as user limit 3
return user.name

Result:

Using limit()

In this query, the find().nodes() statement executes two times, each time using one record from id. With the limit() method, only one node is retrieved each time:

UQL
uncollect ["U02", "U03"] as id
call {
    with id
    find().nodes({_id > id}).limit(1) as n
    return n
}
return n{*}

Result: n

Using OPTIONAL

In this query, the find().nodes() statement executes three times, each time using one record from ID. With the OPTIONAL prefix, the query returns null if no result is found during execution:

UQL
uncollect ["U01", "U22", "C01"] as ID
optional find().nodes({_id == ID}) as n
return n.name

Result:

Without the prefix OPTIONAL, only two records are returned:

UQL
uncollect ["U01", "U22", "C01"] as ID
find().nodes({_id == ID}) as n
return n.name

Result: