WHERE clause¶

The WHERE clause declares one or more filter conditions in the form of boolean value expressions. It usually references one or more properties of a node or edge and filters the results produced by a preceding graph pattern matching clause or statement.

Syntax¶

diagramsource

where_clause

where_clause ::=
    'WHERE' value_expression

Parameters¶

`value_expression`¶

A boolean value expression that functions as a filter condition. Results that do not satisfy the condition are pruned.

For more information, see Boolean type and Expressions.

Examples¶

The following examples assume that the temporary graph #movie_temporary_graph has been created and data has been imported into it.

Filter with one condition¶

'''
USE #movie_temporary_graph {
    TABLE result_table TYPED TABLE {movie STRING, audience INT64, rate DOUBLE}

    MATCH (v@Movie)<-[e@Watch]-(u@`User`)
    WHERE e.rate > 3
    PER PATH {
        EXPORT v.name AS movie, u.id AS audience, e.rate AS rate INTO result_table
    }

    FOR r IN result_table
    RETURN r.movie AS movie, r.audience AS audience, r.rate AS rate
    ORDER BY r.movie ASC, r.audience ASC, r.rate DESC
    LIMIT 3
}
'''

Return:

+---------------+----------+------+
| movie         | audience | rate |
+---------------+----------+------+
| A Close Shave | 16       | 4.0  |
| A Close Shave | 18       | 4.0  |
| A Close Shave | 19       | 4.0  |
+---------------+----------+------+

Filter with multiple conditions¶

'''
USE #movie_temporary_graph {
    TABLE result_table TYPED TABLE {movie STRING, rate DOUBLE}

    MATCH (v@Movie)<-[e@Watch]-(u@`User`)
    WHERE e.rate > 2 AND u.id = 100
    PER PATH {
        EXPORT v.name AS movie, e.rate AS rate INTO result_table
    }

    FOR r IN result_table
    RETURN r.movie AS movie, r.rate AS rate
}
'''