Syntax
<advanced linear composition> ::=
  <query statement> <next statement> [ { <next statement> }... ]

<next statement> ::=
  "NEXT" [ <yield clause> ] <query statement>

<query statement> ::=
  <linear query statement> | <composite query statement>
          
<yield clause> ::= 
  "YIELD" <yield item> [ { "," <yield item> }... ]

<yield item> ::=
  <column name> [ "AS" <binding variable> ]

Details

The conclusion of each <query statement> must contain a RETURN statement, specifying the variables that can be referenced in the <query statement> immediately after NEXT.
The NEXT statement supports the YIELD clause. See NEXT YIELD.

Example Graph


CREATE GRAPH myGraph { 
  NODE User ({name string}),
  NODE Club (),
  EDGE Follows ()-[{}]->(),
  EDGE Joins ()-[{memberNo uint32}]->()
} PARTITION BY HASH(Crc32) SHARDS [1]

Basic Usage

This query returns users who are members of C01 while also followed by U03:

GQL
MATCH ({_id: "C01"})<-[:Joins]-(u1:User)
RETURN u1
NEXT
MATCH ({_id: "U03"})-[:Follows]->(u2:User) WHERE u2 = u1
RETURN u2

Result: u2

_id	_uuid	schema	values
U05	Sys-gen	User	{name: "lionbower"}

This query throws error since name is out of scope:

GQL - Error Occurs
LET name = "rowlock"
RETURN name
NEXT
MATCH ({_id: "C01"})<-[:Joins]-(u:User)
RETURN u
NEXT
RETURN name IN collect_list(u.name)

Using Grouped Result

This query returns the names of users who joined the club with the largest number of members:

GQL
MATCH (c:Club)<-[:Joins]-()
RETURN c, count(c) AS cnt GROUP BY c
ORDER BY cnt DESC LIMIT 1
NEXT
MATCH (c)<-[:Joins]-(u)
RETURN c._id, collect_list(u.name)

Result:

c._id	collect_list(u.name)
C01	["Brainy","lionbower"]

Using Aggregated Result

This query inserts a new Joins edge from U01 to C01 and sets the memberNo property to the next highest value:

GQL
MATCH ({_id: "C01"})<-[e1:Joins]-()
RETURN max(e1.memberNo) AS maxNo
NEXT
MATCH (u {_id: "U01"}), (c {_id: "C01"})
INSERT (c)<-[e2:Joins {memberNo: maxNo + 1}]-(u)
RETURN e2

Result: e2

_uuid	_from	_to	_from_uuid	_to_uuid	schema	values
Sys-gen	U01	C01	UUID of U01	UUID of C01	Joins	{memberNo: 3}

NEXT YIELD

The YIELD clause can be used to select specific variables from the previous query statement and rename them if necessary, making them accessible for reference in the next query statement. Variables not selected with YIELD will no longer be available. If the YIELD clause is omitted, all variables bound in the previous query statement are passed through by default.

This query finds clubs joined by users followed by purplechalk:

GQL
LET name = "purplechalk"
MATCH (:User {name: name})-[:Follows]->(u:User)
RETURN *
NEXT YIELD u
MATCH (u)-[:Joins]->(c:Club)
RETURN u.name, c._id