Add and update documentation on Exists and Count subquery expressions

[gem-neo4j]

No description provided.

[neo-technology-commit-status-publisher]

Looks like you've updated the documentation!

Check out your changes at https://neo4j-docs-cypher-182.surge.sh

[gem-neo4j]

Write Documentation for updated EXISTS and COUNT

[gem-neo4j]

Turned it into a draft as this is targeting 5.3 release :)

[Lojjs]

Overall good, but there are some additional things I think would be good to include/clarify.

[Lojjs]

Not your fault, but I noticed that the Subquery expressions (and some other Expressions sections as well) are missing from this menu: https://neo4j-docs-cypher-182.surge.sh/cypher-manual/5.0/syntax/. In the published docs it is also broken, but in a different way. Perhaps something we should do a card to the docs team for?

[gem-neo4j]

Nice spotting :) Easy enough for me to add the links, what is broken though? I can make a card reporting that

[Lojjs]

In the published docs here https://neo4j.com/docs/cypher-manual/current/syntax/ there are another subset of the links under Expressions that are missing, weirdly enough

[Lojjs]

Looks good now :)

[JPryce-Aklundh]

Suggested change

	Any non-writing query is allowed, how it differs from regular queries is that the final `RETURN` clause may be omitted
	Any non-writing query is allowed. `EXISTS` subqueries differ from regular queries in that the final `RETURN` clause may be omitted,

[JPryce-Aklundh]

Suggested change

	It is worth noting that the `MATCH` keyword can be omitted in subqueries in the case where the `EXISTS` consists of only
	It is worth noting that the `MATCH` keyword can be omitted in subqueries in cases where the `EXISTS` consists of only

[JPryce-Aklundh]

Suggested change

	unlike the case for `CALL` subqueries, xref::clauses/call-subquery.adoc#subquery-correlated-importing[where they require importing].
	In this regard, `EXISTS` subqueries are different from `CALL` subqueries, xref::clauses/call-subquery.adoc#subquery-correlated-importing[which do require importing].

[JPryce-Aklundh]

Is the "at least" part necessary here?

Suggested change

	Here is the result that shows if at least one row is returned from the union of 2 queries.
	The result of returning one row from a union of two queries is shown below.

[gem-neo4j]

Actually, this one doesn't make sense either, it isn't the result of returning one row, it is that if one of the union branches was to return at least one row, the entire exists evaluates to true

[JPryce-Aklundh]

Is there a different way to say "will not go out of scope" here? I am a little confused by the sentence. Maybe it could be rephrased like this:

Suggested change

	Variables from the outside scope will not go out of scope when using a `WITH`, they are visible for the entirety of the subquery,
	Variables from the outside scope are visible for the entirety of the subquery when using a `WITH` clause.

[gem-neo4j]

This isn't quite what I meant, so variables are visible for the entire subquery, even if you were to use a WITH clause

[JPryce-Aklundh]

Suggested change

	Shadowing of an outside scope variable is when a newly introduced variable inside the inner scope is defined with the same name as one from the outside scope.
	An outside scope variable is shadowed when a newly introduced variable within the inner scope is defined with the same variable.

[JPryce-Aklundh]

Suggested change

	Here is an example where a `WITH` clause introduces a new variable,
	In the below example, a `WITH` clause introduces a new variable.

[JPryce-Aklundh]

Suggested change

	and the outer scope variable person being referenced is still available after:
	The outer scope variable `person` referenced in the main query is still available after the subquery.

[gem-neo4j]

It isn't available "after" the subquery, but after the WITH clause though 🤔

[JPryce-Aklundh]

Suggested change

	`COUNT` subqueries do not require a `RETURN` clause at the end of the subquery, but if one is present, it does not
	`COUNT` subqueries do not require a `RETURN` clause at the end of the subquery. If one is present, it does not need to be aliased.```

[JPryce-Aklundh]

Suggested change

	need to be aliased, a difference from xref::clauses/call-subquery.adoc[`CALL` subqueries].
	This is a difference compared to from xref::clauses/call-subquery.adoc[`CALL` subqueries].

[JPryce-Aklundh]

LGTM! 👍