Query find().nodes() can apply filters on nodes and return those that meet the requirement. This is very similar to table query in traditional database.

Syntax:

• Statement alias: supported (NODE)
• Prefix: OPTIOANL (returns null for any subquery that finds no result)
• Optional parameters:

An alias nodes will be automatically defined by system when there is no manually defined alias at the end of the node query statement; in this case user cannot use nodes to define alias for other data in the subsequent UQL statement, otherwise error of duplicated name will be triggered.

Sample graph: (to be used for the following examples)

create().node_schema("professor").node_schema("student")
create().node_property(@*, "age", int32).node_property(@*, "email", string)
insert().into(@professor).nodes([{_id:"P001",_uuid:1,age:53,email:"test@yahoo.cn"},{_id:"P002",_uuid:2,age:27,email:"test@ultipa.com"}])
insert().into(@student).nodes([{_id:"S001",_uuid:3,age:27,email:"test@yeah.net"},{_id:"S002",_uuid:4,age:20,email:"test@w3.org"},{_id:"S003",_uuid:5,age:25,email:"test@gmail.com"}])

No Filter

Example: Find any node, carry all properties

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

|--------------- @professor --------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| P001  |   1   |  53   | test@yahoo.cn   |
| P002  |   2   |  27   | test@ultipa.com |

|---------------- @student ---------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| S001  |   3   |  27   | test@yeah.net   |
| S002  |   4   |  20   | test@w3.org     |
| S003  |   5   |  25   | test@gmail.com  |

Filter ID

Example: Find node with _id S001, carry all properties

find().nodes({_id == "S001"}) as n
return n{*}

|---------------- @student ---------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| S001  |   3   |  27   | test@yeah.net   |

Example: Find nodes with _uuid 1 or 3, carry all properties

find().nodes([1,3]) as n
return n{*}

|--------------- @professor --------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| P001  |   1   |  53   | test@yahoo.cn   |

|---------------- @student ---------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| S001  |   3   |  27   | test@yeah.net   |

Filter Schema

Example: Find nodes of @student, carry all properties

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

|---------------- @student ---------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| S001  |   3   |  27   | test@yeah.net   |
| S002  |   4   |  20   | test@w3.org     |
| S003  |   5   |  25   | test@gmail.com  |

Filter Property

Example: Find nodes with age greater than 25, carry all properties

find().nodes({age > 25}) as n
return n{*}

|--------------- @professor --------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| P001  |   1   |  53   | test@yahoo.cn   |
| P002  |   2   |  27   | test@ultipa.com |

|---------------- @student ---------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| S001  |   3   |  27   | test@yeah.net   |

Filter Schema & Property

Example: Find nodes of @student with age greater than 25, carry all properties

find().nodes({@student.age > 25}) as n
return n{*}

|---------------- @student ---------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| S001  |   3   |  27   | test@yeah.net   |

limit()

Example: Find 3 nodes, carry all properties

find().nodes().limit(3) as n
return n{*}

|--------------- @professor --------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| P001  |   1   |  53   | test@yahoo.cn   |
| P002  |   2   |  27   | test@ultipa.com |

|---------------- @student ---------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| S001  |   3   |  27   | test@yeah.net   |

Default Statement Alias

Example: Find 3 nodes, carry all properties

find().nodes().limit(3)
return nodes{*}

|--------------- @professor --------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| P001  |   1   |  53   | test@yahoo.cn   |
| P002  |   2   |  27   | test@ultipa.com |

|---------------- @student ---------------|
|  _id  | _uuid |  age  |       email     |
|-------|-------|-------|-----------------|
| S001  |   3   |  27   | test@yeah.net   |

OPTIONAL

Example: Find nodes with age greater than 55, carry all properties; return null if no result

optional find().nodes({age > 55}) as n
return n{*}

null

Analysis: This query will give no return if not using OPTIONAL.