SURF-768 Documentation for cardinality function#1574
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| | *Returns* 3+| `INTEGER` | ||
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| This function was introduced as part of Cypher's xref:appendix/gql-conformance/index.adoc[] (optional GQL feature GF12, "CARDINALITY function"). |
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Not sure if this is needed, it offers new functionality unlike the alias ones you did, maybe Jens has an opinon on that though
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Agreed - this is not necessary here.
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| - For a `LIST<ANY>`, `cardinality()` returns the same result as xref:functions/scalar.adoc#functions-size[`size()`]. | ||
| - For a `MAP`, it returns the same result as `size(keys(map))`. |
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Can you switch the order to match the description?
| - For a `PATH`, it returns the total number of nodes and relationships in the path. | ||
| - For a non-empty path, `cardinality(p) = 2 * length(p) + 1`. | ||
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| Binding table reference values are not supported in Cypher, so this is an intentional subset of the full GQL cardinality expression. |
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This is not relevant here, it is most likely confusing to users who don't know GQL well
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| | `cardinality(null)` returns `null`. | ||
| | For a `LIST<ANY>`, only top-level elements are counted; nested lists count as a single element. | ||
| | `cardinality()` on values other than a `LIST<ANY>`, `MAP`, `PATH`, or `null` will fail the query. |
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This is true of all functions, I don't think we normally say that
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| RETURN cardinality([1, 2, 3]); | ||
| MATCH p = (a)-[r]->(b) RETURN cardinality(p), length(p); |
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You're missing the map case, also remove length as it isn't relevant here.
Co-authored-by: Gem Lamont <106068376+gem-neo4j@users.noreply.github.com>
Co-authored-by: Gem Lamont <106068376+gem-neo4j@users.noreply.github.com>
Co-authored-by: Jens Pryce-Åklundh <112686610+JPryce-Aklundh@users.noreply.github.com>
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This PR includes documentation updates Updated pages: |
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https://linear.app/neo4j/issue/SURF-768/gql-compliance-cardinality-function