Add mandatory GQL features

modules/ROOT/content-nav.adoc

@@ -125,6 +125,7 @@
 * Appendix
 ** xref:styleguide.adoc[]
 ** xref:appendix/gql-conformance/index.adoc[]
+*** xref:appendix/gql-conformance/supported-mandatory.adoc[]
 *** xref:appendix/gql-conformance/unsupported-mandatory.adoc[]
 *** xref:appendix/gql-conformance/supported-optional.adoc[]
 *** xref:appendix/gql-conformance/analogous-cypher.adoc[]

modules/ROOT/pages/appendix/gql-conformance/analogous-cypher.adoc

@@ -6,7 +6,7 @@ This page lists optional GQL features that have analogous but not identical Cyph
 Optional GQL features are assigned a feature ID code.
 These codes order the features in the table below.
 
-[options="header",cols="a,3a,5a"]
+[options="header",cols="2a,3a,5a"]
 |===
 | GQL Feature ID
 | Description
@@ -16,16 +16,6 @@ These codes order the features in the table below.
 | `ELEMENT_ID` function
 | GQL's `ELEMENT_ID()` function is equivalent to Cypher's xref:functions/scalar.adoc#functions-elementid[`elementId()`] function.
 
-| GF01
-| Enhanced numeric functions
-| GQL supports `CEILING()` as a synonym to the `CEIL()` function.
-Cypher only supports xref:functions/mathematical-numeric.adoc#functions-ceil[`ceil()`].
-
-| GF03
-| Logarithmic functions
-| * Cypher uses the xref:functions/mathematical-logarithmic.adoc#functions-log[`log()`] function instead of GQL's `LN()` function.
-* Cypher uses the xref:syntax/operators.adoc#syntax-using-the-exponentiation-operator[exponentiation operator (`^`)] instead of GQL's `POWER()` function.
-
 | GF04
 | Enhanced path functions
 | GQL's `PATH_LENGTH()` function is equivalent to Cypher's xref:functions/scalar.adoc#functions-length[`length()`] function.
@@ -69,25 +59,6 @@ Unlike the `FOR` statement, `UNWIND` does not support yielding indexes and offse
 | 64-bit floating number
 | GQL’s `FLOAT64`  type is equivalent to Cypher’s xref:values-and-types/property-structural-constructed.adoc#_property_type_details[`FLOAT`] type.
 
-| GV39
-| xref:values-and-types/temporal.adoc[Temporal types: date, local datetime, and local time support]
-| Cypher supports GQL’s local temporal types, with the following exceptions:
-
-* GQL defines a parameterless version of the xref:functions/temporal/index.adoc#functions-date[`date()`] function not in Cypher: `CURRENT_DATE`.
-* GQL’s `LOCAL_TIME()` function is equivalent to Cypher’s xref:functions/temporal/index.adoc#functions-localtime[`localtime()`] function.
-GQL also defines a parameterless version of the function not in Cypher: `LOCAL_TIME`.
-* GQL’s `LOCAL_DATETIME()` function is equivalent to Cypher’s xref:functions/temporal/index.adoc#functions-localdatetime[`localdatetime()`] function.
-GQL also defines a parameterless version of the function not in Cypher: `LOCAL_DATETIME`.
-
-| GV40
-| xref:values-and-types/temporal.adoc[Temporal types: zoned datetime and zoned time support]
-| Cypher supports GQL’s zoned temporal types, with the following exceptions:
-
-* GQL’s `ZONED_TIME()` function is equivalent to Cypher’s xref:functions/temporal/index.adoc#functions-time[`time()`] function.
-GQL also defines a parameterless version of the function not in Cypher: `CURRENT_TIME`.
-* GQL’s `ZONED_DATETIME()` function is equivalent to Cypher’s xref:functions/temporal/index.adoc#functions-datetime[`datetime()`] function.
-GQL also defines a parameterless version of the function not in Cypher: `CURRENT_TIMESTAMP`.
-
 | GV45
 | Record types
 | GQL's open `RECORD` type is equivalent to the xref:values-and-types/maps.adoc[`MAP`] type in Cypher.

modules/ROOT/pages/appendix/gql-conformance/index.adoc

@@ -1,7 +1,7 @@
 :description: Overview of Cypher's conformance to GQL.
 = GQL conformance
 
-*Last updated*: 11 June 2024 +
+*Last updated*: 5 July 2024 +
 *Neo4j version*: 5.21
 
 GQL is the new link:https://www.iso.org/home.html[ISO] International Standard query language for graph databases.
@@ -19,16 +19,15 @@ WHERE a.name = 'Tom Hanks'
 RETURN m.title
 ----
 
-Neo4j is working towards full GQL conformance (meaning full support of its mandatory features).
-There are, however, currently some mandatory GQL features not implemented in Cypher.
+Cypher supports the majority of mandatory GQL features.
+For a full list, see xref:appendix/gql-conformance/supported-mandatory.adoc[].
+There are, however, currently a few mandatory GQL features not implemented in Cypher.
 These are listed in the page xref:appendix/gql-conformance/unsupported-mandatory.adoc[].
 
 Neo4j is also working towards increasing its support of optional GQL features.
 These are listed in the page xref:appendix/gql-conformance/supported-optional.adoc[].
 
 Additionally, some optional GQL features not yet implemented in Cypher already have analogous Cypher equivalents.
-For example, Cypher and GQL support a function to return the local time.
-In Cypher, this is called xref:functions/temporal/index.adoc#functions-localtime[`localtime()`]; in GQL, it is called `LOCAL_TIME()`.
 These features are listed in the page xref:appendix/gql-conformance/analogous-cypher.adoc[].
 
 [[gql-minimum-conformance]]
@@ -43,5 +42,5 @@ Neo4j 5.14 added support for JavaSE 21 and version 15 of the Unicode Standard.
 For more information, see xref:syntax/parsing.adoc##_using_unicodes_in_cypher[Parsing -> Using Unicode in Cypher].
 * Cypher supports the following mandatory GQL property types: `BOOLEAN` (`BOOL`), `FLOAT` footnote:[The `FLOAT` type in Cypher always represents a 64-bit double-precision floating point number.], `INTEGER` (`SIGNED INTEGER`, or `INT`)footnote:[The `INTEGER` type in Cypher always represents a 64-bit `INTEGER`.], and `STRING` (`VARCHAR`).
 +
-Cypher also supports: `DATE`, `DURATION`, `LIST<INNER_TYPE NOT NULL>` (`ARRAY<INNER_TYPE NOT NULL>`, `INNER_TYPE LIST`, or `INNER_TYPE ARRAY`)footnote:[The `INNER_TYPE` cannot be a `LIST` type.], `LOCAL DATETIME` (`TIMESTAMP WITHOUT TIMEZONE`), `LOCAL TIME` (`TIME WITHOUT TIME ZONE`), `POINT`, `ZONED DATETIME` (`TIME WITH TIMEZONE`), and `ZONED TIME` (`TIMESTAMP WITH TIMEZONE`).
+Cypher also supports the following optional GQL property types: `DATE`, `DURATION`, `LIST<INNER_TYPE NOT NULL>` (`ARRAY<INNER_TYPE NOT NULL>`, `INNER_TYPE LIST`, or `INNER_TYPE ARRAY`)footnote:[The `INNER_TYPE` cannot be a `LIST` type.], `LOCAL DATETIME` (`TIMESTAMP WITHOUT TIMEZONE`), `LOCAL TIME` (`TIME WITHOUT TIME ZONE`), `POINT`, `ZONED DATETIME` (`TIME WITH TIMEZONE`), and `ZONED TIME` (`TIMESTAMP WITH TIMEZONE`).
 For more information, see xref:values-and-types/property-structural-constructed.adoc#_property_types[Values and types -> property types].

modules/ROOT/pages/appendix/gql-conformance/supported-mandatory.adoc

@@ -0,0 +1,231 @@
+:description: Information about mandatory GQL features supported by Cypher.
+= Supported mandatory GQL features
+
+Unlike optional GQL features, mandatory GQL features are not assigned a GQL feature ID code.
+The below table is instead listed in order of their appearance in the link:https://www.iso.org/standard/76120.html[ISO/IEC 39075:2024(en) GQL Standard].
+
+[options="header",cols="2a,3a,2a,5a"]
+|===
+| GQL Standard subclause
+| Description
+| Documentation
+| Comment
+
+| 4.11
+| Graph pattern matching
+| xref:patterns/index.adoc[]
+|
+
+| 4.13
+| GQL object types
+| xref:values-and-types/property-structural-constructed.adoc#structural-types[Structural types],  xref:values-and-types/property-structural-constructed.adoc#type-synonyms[Types and their synonyms].
+| Includes: `NODE` (`ANY NODE`, `VERTEX`, `ANY VERTEX`) and `RELATIONSHIP` (`ANY RELATIONSHIP`, `EDGE`, `ANY EDGE`).
+
+| 4.16
+| Predefined value types
+| xref:values-and-types/property-structural-constructed.adoc#property-types[Property types], xref:values-and-types/property-structural-constructed.adoc#type-synonyms[Types and their synonyms].
+| Includes: `BOOLEAN` (`BOOL`), `FLOAT`, `INTEGER` (`SIGNED INTEGER`, `INT`), and `STRING` (`VARCHAR`).
+
+Cypher supports the boolean type predicate for `TRUE`, `FALSE`, and `NULL` but does not support the GQL keyword `UNKNOWN`.
+
+| 13.2
+| <insert statement>
+| xref:clauses/create.adoc#insert-as-synonym-of-create[`INSERT`]
+|
+
+| 13.3
+| <set statement>
+| xref:clauses/set.adoc[`SET`]
+| GQL’s `SET` has no order dependencies because all right-hand side operations are completed before any assignments occur.
+In Cypher’s `SET`, the order of rows can affect the outcome because changes made during execution may depend on the sequence of assignments.
+The only way to guarantee row order in Neo4j is to use xref:clauses/order-by.adoc[`ORDER BY`]. 
+
+| 13.4
+| <remove statement>
+| xref:clauses/remove.adoc[`REMOVE`]
+|
+
+| 13.5
+| <delete statement>
+| xref:clauses/delete.adoc[`DELETE`]
+|
+
+| 14.4
+| <match statement>
+| xref:clauses/match.adoc[`MATCH`], xref:clauses/optional-match.adoc[`OPTIONAL MATCH`]
+| 
+
+| 14.9
+| <order by and page statement>
+| xref:clauses/skip.adoc[`SKIP`]
+| Cypher only supports `SKIP`, which is a GQL-supported synonym to `OFFSET`.
+
+
+| 14.10
+| <primitive result statement>
+| xref:clauses/finish.adoc[`FINISH`]
+|
+
+| 14.11
+| <return statement>
+| xref:clauses/return.adoc[`RETURN`]
+|
+
+| 15.1
+| <call procedure statement> and <procedure call>
+| xref:clauses/call.adoc[`CALL` procedures], xref:subqueries/call-subquery.adoc[`CALL` subqueries].
+| GQL defines an `OPTIONAL CALL` statement, enabling optional procedure and subquery calling.
+This is not available in Cypher.
+
+| 15.2
+| <inline procedure call>
+| xref:subqueries/call-subquery.adoc[`CALL` subqueries].
+| GQL either imports variables implicitly, or explicitly using a variable scope clause.
+In Cypher, `CALL` subqueries require an explicit importing `WITH` clause.
+
+| 15.3
+| <named procedure call>
+| xref:clauses/call.adoc[`CALL` procedure]
+|
+
+| 16.2
+| <limit clause>
+| xref:clauses/limit.adoc[`LIMIT`]
+|
+
+| 16.4
+| <graph pattern>
+| xref:patterns/reference.adoc#graph-patterns[Graph patterns]
+|
+
+| 16.5
+| <insert graph pattern>
+| xref:clauses/create.adoc#[`CREATE`]
+|
+
+| 16.6
+| <order by clause>
+| xref:clauses/order-by.adoc[`ORDER-BY`]
+|
+
+| 16.7
+| <path pattern expression>
+| xref:patterns/reference.adoc#path-patterns[Path patterns]
+|
+
+| 16.8
+| <label expression>
+| xref:patterns/reference.adoc#label-expressions[Label expressions]
+|
+
+| 16.9
+| <path variable reference>
+| xref:patterns/reference.adoc[Patterns -> Syntax and semantics]
+|
+
+| 16.11
+| <graph pattern quantifier>
+| xref:patterns/reference.adoc#quantifiers[Quantifiers]
+|
+
+| 16.17
+| <sort specification list>
+| xref:clauses/order-by.adoc#order-nodes-in-descending-order[Order results in ascending or descending order]
+|
+
+| 16.19
+| <offset clause>
+| xref:clauses/skip.adoc[`SKIP`]
+| Cypher only supports `SKIP` , which is a GQL-supported synonym to `OFFSET`.
+
+| 19.3
+| <comparison predicate>
+| xref:syntax/operators.adoc##query-operators-comparison[Comparison operators]
+|
+
+| 19.4
+| <exists predicate>
+| xref:functions/predicate.adoc#function-exists[`exists()`]
+|
+
+| 19.5
+| <null predicate>
+| xref:values-and-types/type-predicate.adoc#type-predicate-null[Type predicate expressions for `NULL`]
+|
+
+| 19.6
+| <value type predicate>
+| xref:values-and-types/type-predicate.adoc#[]
+|
+
+| 19.7
+| <normalized predicate>
+| xref:syntax/operators.adoc#match-string-is-normalized[`IS NORMALIZED`], xref:syntax/operators.adoc#match-string-is-not-normalized[`IS NOT NORMALIZED`]
+|
+
+| 20.2
+| <value expression primary>
+| xref:queries/expressions.adoc[]
+|
+
+| 20.3
+| <value specification>
+| 
+| GQL defines the `SESSION_USER` value expression, which enables accessing a user’s username within a query.
+In Cypher, current user details can be seen using the link:{neo4j-docs-base-uri}/operations-manual/{page-version}/authentication-authorization/manage-users/#access-control-current-users[`SHOW CURRENT USER` command].
+
+| 20.7
+| <case expression>
+| xref:queries/case.adoc[`CASE`], xref:functions/scalar.adoc#functions-nullIf[`nullIf()`], xref:functions/scalar.adoc#functions-coalesce[`coalesce()`]
+|
+
+| 20.9
+| <aggregate function>
+| xref:functions/aggregating.adoc#functions-avg[`avg()`], xref:functions/aggregating.adoc#functions-count[`count()`], xref:functions/aggregating.adoc#functions-max[`max`], xref:functions/aggregating.adoc#functions-mind[`min()`], xref:functions/aggregating.adoc#functions-sum[`sum()`]
+| Cypher and GQL handle `NULL` values differently for the `sum()` function when queries return 0 rows. 
+For example, `RETURN sum(<expr>)` on an empty table returns `NULL` in GQL, but in Cypher it returns `0`.
+
+| 20.11
+| <property reference>
+| xref:queries/concepts.adoc[Core concepts]
+|
+
+| 20.21
+| <numeric value expression>
+| xref:syntax/operators.adoc#query-operators-mathematical[Mathematical operators]
+|
+
+| 20.22
+| <numeric value function>
+| xref:functions/scalar.adoc#functions-char_length[`char_length()`], xref:functions/scalar.adoc#functions-character_length[`character_length()`]
+|
+
+| 20.23
+| <string value expression>
+| xref:syntax/operators.adoc#syntax-concatenating-two-strings-doublebar[`STRING` concatenation operator (`\|\|`)]
+|
+
+| 20.24
+| <character string function>
+| xref:functions/string.adoc#functions-left[`left()`], xref:functions/string.adoc#functions-lower[`lower()`], xref:functions/string.adoc#functions-normalize[`normalize()`], xref:functions/string.adoc#functions-right[`right()`], xref:functions/string.adoc#functions-trim[`trim()`], xref:functions/string.adoc#functions-upper[`upper()`]
+| In GQL, `TRIM()` removes only space characters.
+In Cypher, `trim()` removes any whitespace character.
+
+| 21.1
+| Names and variables
+| xref:syntax/index.adoc[]
+| Cypher supports GQL’s lexical elements, with the following caveats:
+
+* GQL allows for extended parameter identifiers.
+For example: `RETURN $0hello` is allowed in GQL but not Cypher.
+* GQL allows identifiers that are not variables to be delimited with both backticks and quotes.
+Cypher only allows backticks.
+For example: `MATCH (n) RETURN n."a prop"` is allowed in GQL but not Cypher.
+
+| 22.15
+| Grouping operations
+| xref:functions/aggregating.adoc##counting_with_and_without_duplicates[Counting with and without duplicates]
+|
+
+|===
+