Reference operators¶
NGQL provides reference operators to represent a property in a WHERE
or YIELD
clause, or the output of the statement before the pipe operator in a composite query.
OpenCypher compatibility¶
Reference operators apply to native nGQL only.
Reference operator List¶
| Reference operator | Description |
|--------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------|
| $^
| Refers to a source vertex property. For more information, see Property reference. |
| $$
| Refers to a destination vertex property. For more information, see Property reference. |
| $-
| Refers to the output of the statement before the pipe operator in a composite query. For more information, see Pipe. |
Examples¶
# The following example returns the age of the source vertex and the destination vertex.
nebula> GO FROM "player100" OVER follow YIELD properties($^).age AS SrcAge, properties($$).age AS DestAge;
+--------+---------+
| SrcAge | DestAge |
+--------+---------+
| 42 | 36 |
| 42 | 41 |
+--------+---------+
# The following example returns the name and team of the players that player100 follows.
nebula> GO FROM "player100" OVER follow \
YIELD dst(edge) AS id | \
GO FROM $-.id OVER serve \
YIELD $^.player.name AS Player, properties($$).name AS Team;
+-----------------+-----------+
| Player | Team |
+-----------------+-----------+
| "Tony Parker" | "Spurs" |
| "Tony Parker" | "Hornets" |
| "Manu Ginobili" | "Spurs" |
+-----------------+-----------+