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User-defined variables

User-defined variables allow passing the result of one statement to another.

OpenCypher compatibility

In openCypher, when you refer to the vertex, edge, or path of a variable, you need to name it first. For example:

nebula> MATCH (v:player{name:"Tim Duncan"}) RETURN v;
| v                                                  |
| ("player100" :player{name: "Tim Duncan", age: 42}) |

The user-defined variable in the preceding query is v.


In a pattern of a MATCH statement, you cannot use the same edge variable repeatedly. For example, e cannot be written in the pattern p=(v1)-[e*2..2]->(v2)-[e*2..2]->(v3).

Native nGQL

User-defined variables are written as $var_name. The var_name consists of letters, numbers, or underline characters. Any other characters are not permitted.

The user-defined variables are valid only at the current execution (namely, in this composite query). When the execution ends, the user-defined variables will be automatically expired. The user-defined variables in one statement CANNOT be used in any other clients, executions, or sessions.

You can use user-defined variables in composite queries. Details about composite queries, see Composite queries.


  • User-defined variables are case-sensitive.
  • To define a user-defined variable in a compound statement, end the statement with a semicolon (;). For details, please refer to the nGQL Style Guide.


nebula> $var = GO FROM "player100" OVER follow YIELD dst(edge) AS id; \
        GO FROM $ OVER serve YIELD properties($$).name AS Team, \
        properties($^).name AS Player;
| Team      | Player          |
| "Spurs"   | "Tony Parker"   |
| "Hornets" | "Tony Parker"   |
| "Spurs"   | "Manu Ginobili" |

Last update: February 19, 2024