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User-defined variables

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

OpenCypher variables

In openCypher, when you refer to a variable of vertex, edge or path, you need to name it first. The name you give to the pattern is a variable. 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.

nGQL extensions

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

User-defined variables can only be used in one execution. For example, you can use user-defined variables in composite queries separated by semicolon ; or pipe |. Details about composite queries, see Composite queries.


A user-defined variable is valid only at the current session and execution.

A user-defined variable in one statement CANNOT be used in either other clients or other executions. The statement that defines the user-defined variable and the statement that uses it must be submitted together. When this session ends, the user-defined variable is automatically expired.


User-defined variables are case-sensitive.


nebula> $var = GO FROM "player100" OVER follow YIELD follow._dst AS id; \
GO FROM $ OVER serve YIELD $$ AS Team, \
$^ AS Player;
| Team    | Player      |
| Nuggets | Tony Parker |

Last update: May 20, 2021
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