eeshwarg opened a new pull request, #2468:
URL: https://github.com/apache/age/pull/2468
Apache AGE's MATCH grammar rejects openCypher's relationship-type
alternation syntax - `MATCH ()-[:A|B]->()` fails at parse time with `syntax
error at or near "|"`. For example, a query like `SELECT * FROM cypher('kg_s7',
$$ MATCH (p)-[:WORKS_AT|REPORTS_TO]->(c) RETURN c $$) AS (c agtype);` throws a
syntax error. A workaround for this today is to run something like `SELECT *
FROM cypher('kg_s7', $$ MATCH (p)-[r]->(c) WHERE type(r) IN
['WORKS_AT','REPORTS_TO'] RETURN c $$) AS (c agtype);`.
This change enables support for relationship-type alternation in accordance
with the openCypher standard. Changes are made in the grammar, AST and during
transformation from the AST to Postgres `Query` struct by adding the types to
the `quals` list.
Variable-length relationship patterns with alternation `([:A|B*1..2])` are
explicitly rejected with `ERRCODE_FEATURE_NOT_SUPPORTED`.
Testing:
- Added regress test with cases with directed/undirected edges, and variable
length edges
Future work:
- openCypher also supports node-type alternation (like n:Person|Customer),
which could be added to AGE in a future PR
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