Document EF.Functions.JsonPathExists() (#5272)

See dotnet/efcore#31136

Author: roji

entity-framework/core/providers/sql-server/functions.md

@@ -236,7 +236,8 @@ stringValue.TrimStart()                                                 | LTRIM(
 
 .NET                                                              | SQL                                                       | Added in
 ----------------------------------------------------------------- | --------------------------------------------------------- | --------
-EF.Functions.JsonContains(json, searchValue, path?, searchMode?)  | JSON_CONTAINS(@json, @searchValue, @path?, @searchMode?)  | EF Core 11.0
+EF.Functions.JsonContains(json, searchValue, path?, searchMode?)  | JSON_CONTAINS(@json, @searchValue, @path?, @searchMode?)  | EF 11.0
+EF.Functions.JsonPathExists(json, path)                           | JSON_PATH_EXISTS(@json, @path)                            | EF 11.0
 
 ## Miscellaneous functions
 

entity-framework/core/what-is-new/ef-core-11.0/whatsnew.md

@@ -104,6 +104,30 @@ ORDER BY (
 
 Similarly, `MinByAsync` orders ascending and returns the element with the minimum value for the key selector.
 
+### EF.Functions.JsonPathExists()
+
+EF Core 11 introduces `EF.Functions.JsonPathExists()`, which checks whether a given JSON path exists in a JSON document. On SQL Server, this translates to the [`JSON_PATH_EXISTS`](/sql/t-sql/functions/json-path-exists-transact-sql) function (available since SQL Server 2022).
+
+The following query filters blogs to those whose JSON data contains an `OptionalInt` property:
+
+```csharp
+var blogs = await context.Blogs
+    .Where(b => EF.Functions.JsonPathExists(b.JsonData, "$.OptionalInt"))
+    .ToListAsync();
+```
+
+This generates the following SQL:
+
+```sql
+SELECT [b].[Id], [b].[Name], [b].[JsonData]
+FROM [Blogs] AS [b]
+WHERE JSON_PATH_EXISTS([b].[JsonData], N'$.OptionalInt') = 1
+```
+
+`EF.Functions.JsonPathExists()` accepts a JSON value and a JSON path to check for. It can be used with scalar string properties, complex types, and owned entity types mapped to JSON columns.
+
+For the full `JSON_PATH_EXISTS` SQL Server documentation, see [`JSON_PATH_EXISTS`](/sql/t-sql/functions/json-path-exists-transact-sql).
+
 ## Cosmos DB
 
 <a name="cosmos-transactional-batches"></a>