add count example

Author: JPryce-Aklundh

modules/ROOT/pages/queries/composed-queries/conditional-queries.adoc

@@ -52,7 +52,7 @@ If no `WHEN` branches are executed and an `ELSE` branch exists, it is executed.
 If no `WHEN` branches evaluates to `true` and no `ELSE` branch is present, no branches are executed and no rows are produced.
 The following examples demonstrates this logic:
 
-.`WHEN` logic
+.Conditional logic
 [source, cypher]
 ----
 WHEN false THEN RETURN 1 AS x
@@ -247,7 +247,7 @@ RETURN n.name AS name, ageGroup, manager
 | "Charlie" | "Veteran" | [["Daniel", "Senior"]]
 | "Daniel"  | "Senior"  | [["Peter", "Senior"]]
 | "Eskil"   | "Senior"  | [["Peter", "Senior"]]
-| "Peter"   | "Senior"  | [[NULL, NULL]]
+| "Peter"   | "Senior"  | \[[NULL, NULL]]
 
 3+d| Rows: 6
 |===

modules/ROOT/pages/subqueries/call-subquery.adoc

@@ -488,7 +488,7 @@ Now all `Player` nodes, regardless of whether they have any `PLAYS_FOR` relation
 [[conditional-call]]
 == Conditional `CALL` subqueries
 
-`WHEN` can be used inside `CALL` subqueries to execute branches only when a condition evaluates to `true`.
+`WHEN` can be used inside `CALL` subqueries to execute branches conditionally when a predicate evaluates to `true`.
 Note that the names and the number of columns returned by the different `WHEN` branches must be identical.
 For more information, see xref:queries/composed-queries/conditional-queries.adoc#conditional-subqueries[Conditional queries -> Conditional subqueries].
 

modules/ROOT/pages/subqueries/collect.adoc

@@ -74,9 +74,11 @@ RETURN person.name as name, COLLECT {
 2+d|Rows: 3
 |===
 
+[role=label--new-2025.02]
+[[conditional-collect]]
 == Conditional `COLLECT` subquery
 
-`WHEN` can be used inside `COLLECT` subqueries to execute branches only when a condition evaluates to `true`.
+`WHEN` can be used inside `COLLECT` subqueries to execute branches conditionally when a predicate evaluates to `true`.
 Note that the names and the number of columns returned by the different `WHEN` branches must be identical.
 For more information, see xref:queries/composed-queries/conditional-queries.adoc#conditional-subqueries[Conditional queries -> Conditional subqueries].
 
@@ -94,7 +96,7 @@ RETURN n.name AS name,
          ELSE {
           RETURN 'Cat owner' AS petStatus
          }
-} AS petStatus
+       } AS petStatus
 ----
 
 [role="queryresult",options="header,footer",cols="2*<m"]

modules/ROOT/pages/subqueries/count.adoc

@@ -71,6 +71,46 @@ RETURN person.name AS name
 1+d|Rows: 1
 |===
 
+[role=label--new-2025.02]
+[[conditional-count]]
+== Conditional `COUNT` subquery
+
+`WHEN` can be used inside `COUNT` subqueries to execute branches conditionally when a predicate evaluates to `true`.
+Note that the names and the number of columns returned by the different `WHEN` branches must be identical.
+For more information, see xref:queries/composed-queries/conditional-queries.adoc#conditional-subqueries[Conditional queries -> Conditional subqueries].
+
+In the example below, the `WHEN` branch is executed if a person has no cat (`c IS NULL`), counting their dogs.
+The `ELSE` branch runs for those who have a cat. 
+
+.Conditional `COUNT` subquery
+[source, cypher]
+----
+MATCH (p:Person)
+OPTIONAL MATCH (p)-[:HAS_CAT]->(c)
+RETURN p.name AS person, c IS NOT NULL AS hasCat,
+       COUNT {
+          WHEN c IS NULL THEN {
+           MATCH (p)-[:HAS_DOG]->(dog)
+           RETURN dog.name AS petOwner
+          }
+          ELSE {
+           MATCH (p)-[:HAS_CAT]->(cat)
+           RETURN cat.name AS petOwner
+          }
+         } AS howManyPets
+----
+
+[role="queryresult",options="header,footer",cols="3*<m"]
+|===
+| name        | has Cat | howManyPets
+
+| "Andy"      | FALSE | 1
+| "Timothy"   | TRUE  | 1
+| "Peter"     | FALSE | 2
+
+3+d|Rows: 3
+|===
+
 
 [[count-union]]
 == `COUNT` subquery with a `UNION`

modules/ROOT/pages/subqueries/existential.adoc

@@ -77,7 +77,7 @@ RETURN person.name AS name
 [[conditional-exists]]
 == Conditional `EXISTS` subqueries
 
-`WHEN` can be used inside `EXISTS` subqueries to execute branches only when a condition evaluates to `true`.
+`WHEN` can be used inside `EXISTS` subqueries to execute branches conditionally when a predicate evaluates to `true`.
 Note that the names and the number of columns returned by the different `WHEN` branches must be identical.
 For more information, see xref:queries/composed-queries/conditional-queries.adoc#conditional-subqueries[Conditional queries -> Conditional subqueries].