6.8.3.2 Unnesting of Variable-Length Path Queries

Unnesting of variable-length path queries (such as, SHORTEST or CHEAPEST paths) to obtain a separate row for each vertex or edge along a path is supported.

You can unnest a path aggregation using one of the following options:

• ONE ROW PER MATCH (default option)
• ONE ROW PER VERTEX(vertex_variable)
• ONE ROW PER EDGE(edge_variable)

Note:

Visualization of variable-length path queries using the Graph Visualization application is not supported.

For example, the following PGQL query uses ONE ROW PER EDGE option:

SELECT k.TXN_AMOUNT
FROM MATCH ALL SHORTEST (a:Accounts) -[e:transfers]->* (b:Accounts) 
ONE ROW PER EDGE( k )
WHERE a.ACCT_ID = 284 AND b.ACCT_ID = 616

On execution, the preceding query retrieves one row per edge along a path:

+------------+
| TXN_AMOUNT |
+------------+
| 1000.0     |
| 1000.0     |
| 1000.0     |
+------------+

An example for a query with ONE ROW PER VERTEX option is as follows:

SELECT k.ACCT_ID AS id, k.ACCT_NAME AS name
FROM MATCH ANY SHORTEST (a:Accounts) ((src:Accounts)-[e:transfers]->){1,3}(b:Accounts)
ONE ROW PER VERTEX(k)
WHERE a.ACCT_ID=284 AND b.ACCT_ID=616

On execution, the preceding query retrieves one row per vertex along a path:

+----------------------+
| ACCT_ID | ACCT_NAME  |
+----------------------+
| 616     | Account4   |
| 744     | Account3   |
| 772     | Account2   |
| 284     | Account1   |
+----------------------+