RETURN

RETURN performs functional operations on the alias, and assembles multiple return values to send back to client end. Return values that are heterologous will NOT be trimmed.

Syntax: RETURN <expression> as <alias>, <expression> as <alias>, ...
Input:

• <expression>: Return value
• <alias>: Alias of return value, optional

RETURN clause is usually the last statement of a UQL, but can also be followed by ORDER BY, LIMIT or SKIP. Deduplicating an alias in RETURN clause will not affect its homologous aliases.

For instance, assemble 3 return values, of which n1 is heterologous with the other two; the deduplication against n2.color does NOT affect pnodes(path), which is homologous with n2.color:

UQL
find().nodes() as n1 limit 5
n(3).e()[2].n(as n2) as path
return n1, pnodes(path), dedup(n2.color)

NOTE

For information on how to designate properties to be carried by NODE, EDGE, or PATH in RETURN clause, please refer to Chapter Query - Alias System.

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

Run below UQLs one by one in an empty graphset to create graph data: ```customlang___fold__lang_uql create().node_schema("account").node_schema("movie").edge_schema("rate").edge_schema("wishlist") create().node_property(@*, "name").node_property(@account, "age", int32).node_property(@movie, "year", int32).edge_property(@rate, "score", int32) insert().into(@account).nodes([{_id:"S001", _uuid:1, name:"Pepe", age:24}, {_id:"S002", _uuid:2, name:"Lina", age:23}, {_id:"S003", _uuid:3, name:"Emma", age:26}]) insert().into(@movie).nodes([{_id:"M001", _uuid:4, name:"Léon", year:1994}, {_id:"M002", _uuid:5, name:"Avatar", year:2009}]) insert().into(@rate).edges([{_uuid:1, _from_uuid:1, _to_uuid:4, score:9}, {_uuid:2, _from_uuid:3, _to_uuid:5, score:8}]) insert().into(@wishlist).edges([{_uuid:3, _from_uuid:2, _to_uuid:4}, {_uuid:4, _from_uuid:3, _to_uuid:4}]) ```

Return NODE

Example: Carry all properties

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

Result
|-------- @account ---------|
| _id  | _uuid | name | age |
|------|-------|------|-----|
| S001 | 1     | Pepe | 24  |
| S002 | 2     | Lina | 23  |
| S003 | 3     | Emma | 26  |

Example: Carry some custom properties

UQL
find().nodes() as n
return n{name, year} 

Result
|------ @account -----|
| _id  | _uuid | name |
|------|-------|------|
| S001 | 1     | Pepe |
| S002 | 2     | Lina |
| S003 | 3     | Emma |

|----------- @movie -----------|
| _id  | _uuid |  name  | year |
|------|-------|--------|------|
| M001 | 4     | Léon   | 1994 |
| M002 | 5     | Avatar | 2009 |

Analysis: NODE only carries the properties that it has.

Example: Carry only system properties

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

Result
|--- @movie ---|
| _id  | _uuid |
|------|-------|
| M001 | 4     |
| M002 | 5     |

Return EDGE

Example: Carry all properties

UQL
find().edges({@rate}) as e
return e{*} 

Result
|------------------------ @rate -----------------------|
| _uuid | _from | _to  | _from_uuid | _to_uuid | score |
|-------|-------|------|------------|----------|-------|
|   1   | S001  | M001 | 1          | 4        | 9     |
|   2   | S003  | M002 | 3          | 5        | 8     |

Example: Carry only system properties

UQL
find().edges() as e
return e 

Result
|-------------------- @rate -------------------|
| _uuid | _from | _to  | _from_uuid | _to_uuid |
|-------|-------|------|------------|----------|
|   1   | S001  | M001 | 1          | 4        |
|   2   | S003  | M002 | 3          | 5        |

|------------------ @wishlist -----------------|
| _uuid | _from | _to  | _from_uuid | _to_uuid |
|-------|-------|------|------------|----------|
|   3   | S002  | M001 | 2          | 4        |
|   4   | S003  | M001 | 3          | 4        |

Return PATH

Example: Carry some custom properties

UQL
n({@account}).e({@rate}).n({@movie}) as p
return p{name}{*}

Result
[
  {
    "nodes":[
      {"id":"S001","uuid":"1","schema":"account","values":{"name":"Pepe"}},
      {"id":"M001","uuid":"4","schema":"movie","values":{"name":"Léon"}}
    ],
    "edges":[
      {"uuid":"1","from":"S001","to":"M001","from_uuid":"1","to_uuid":"4","schema":"rate","values":{"score":"9"}}
    ],
    "length":1
  },
  {
    "nodes":[
      {"id":"S003","uuid":"3","schema":"account","values":{"name":"Emma"}},
      {"id":"M002","uuid":"5","schema":"movie","values":{"name":"Avatar"}}
    ],
    "edges":[
      {"uuid":"2","from":"S003","to":"M002","from_uuid":"3","to_uuid":"5","schema":"rate","values":{"score":"8"}}
    ],
    "length":1
  }
]

Example: Carry only system properties

UQL
n({@movie}).e({@rate}).n({@account}).e({@wishlist}).n({@movie}) as p
return p

Result
[
  {
    "nodes":[
      {"id":"M002","uuid":"5","schema":"movie","values":{}},
      {"id":"S003","uuid":"3","schema":"account","values":{}},
      {"id":"M001","uuid":"4","schema":"movie","values":{}}
    ],
    "edges":[
      {"uuid":"2","from":"S003","to":"M002","from_uuid":"3","to_uuid":"5","schema":"rate","values":{}},
      {"uuid":"4","from":"S003","to":"M001","from_uuid":"3","to_uuid":"4","schema":"wishlist","values":{}}
    ],
    "length":2
  }
]

Return TABLE

Example: Find 1-step path @account-@movie, assemble the name of accounts and movies into a table

UQL
n({@account} as a).e({@wishlist}).n({@movie} as b)
return table(a.name, b.name)

Result
| a.name | b.name |
|--------|--------|
| Lina   | Léon   | 
| Emma   | Léon   | 

Return ATTR - Atomic

Example: Return custom properties of nodes independently

UQL
find().nodes() as n
return n.name, n.age, n.year 

Result - n.name
Pepe
Lina
Emma
Léon
Avatar

Result - n.age
24
23
26
null
null

Result - n.year
null
null
null
1994
2009

Analysis: A null will be returned when calling a property that is not existent.

Return ATTR - List

Example: Assemble the name of 1-Hop neighbors of each movie into a list

UQL
khop().n({@movie} as a).e().n() as b
group by a
return a.name, collect(b.name)

Result - a.name
Léon
Avatar

Result - collect(b.name)
["Pepe","Lina","Emma"]
["Emma"]

Valid Return Format

Suppose that nodes, edges, paths, mytable, mylist, mypoint and myitem are aliases of type NODE, EDGE, PATH, TABLE, list, point and others, below return formats are supported: