support for navigation properties in order by added

src/Drivers/EloquentEntitySet.php

@@ -435,6 +435,30 @@ protected function configureBuilder($builder)
 
         $orderby = $this->generateOrderBy();
 
+        // Add LEFT JOINs for navigation properties referenced in $orderby
+        if (!empty($this->orderByNavigationJoins)) {
+            // Qualify SELECT columns to avoid ambiguity with joined tables
+            $builder->select($this->getTable().'.*');
+
+            foreach ($this->orderByNavigationJoins as $joinInfo) {
+                $navigationProperty = $joinInfo['navigationProperty'];
+                $binding = $joinInfo['binding'];
+                $targetSet = $binding->getTarget();
+
+                $constraints = $navigationProperty->getConstraints();
+                foreach ($constraints as $constraint) {
+                    $localColumn = $this->getModel()->qualifyColumn(
+                        $this->getPropertySourceName($constraint->getProperty())
+                    );
+                    $targetTable = $targetSet->getTable();
+                    $targetColumn = $targetTable . '.' .
+                        $targetSet->getPropertySourceName($constraint->getReferencedProperty());
+
+                    $builder->leftJoin($targetTable, $localColumn, '=', $targetColumn);
+                }
+            }
+        }
+
         if ($orderby->hasStatement()) {
             $builder->orderByRaw($orderby->getStatement(), $orderby->getParameters());
         }

src/Drivers/SQL/SQLOrderBy.php

@@ -14,6 +14,13 @@
  */
 trait SQLOrderBy
 {
+    /**
+     * Navigation properties referenced in $orderby that need LEFT JOINs.
+     * Populated by generateOrderBy(), consumed by configureBuilder().
+     * @var array
+     */
+    protected array $orderByNavigationJoins = [];
+
     /**
      * Generate expression for orderby parameters
      * @return SQLExpression
@@ -29,6 +36,7 @@ protected function generateOrderBy(): SQLExpression
         }
 
         $this->assertValidOrderBy();
+        $this->orderByNavigationJoins = [];
 
         $orders = $orderby->getSortOrders();
 
@@ -42,9 +50,40 @@ protected function generateOrderBy(): SQLExpression
             $order = array_shift($orders);
             [$propertyName, $direction] = $order;
 
-            $property = $properties[$propertyName];
+            if (str_contains($propertyName, '/')) {
+                // Navigation property path (e.g., "Status/SortOrder")
+                $segments = explode('/', $propertyName);
+                [$navPropertyName, $targetPropertyName] = $segments;
+
+                $navigationProperty = $this->getType()->getNavigationProperties()->get($navPropertyName);
+                $binding = $this->getBindingByNavigationProperty($navigationProperty);
+                $targetSet = $binding->getTarget();
+                $targetProperty = $targetSet->getType()->getProperty($targetPropertyName);
+
+                // Store join info for configureBuilder()
+                $joinKey = $navPropertyName;
+                if (!isset($this->orderByNavigationJoins[$joinKey])) {
+                    $this->orderByNavigationJoins[$joinKey] = [
+                        'navigationProperty' => $navigationProperty,
+                        'binding' => $binding,
+                    ];
+                }
+
+                // Generate fully qualified column: "target_table"."target_column"
+                $targetTable = $targetSet->getTable();
+                $targetColumn = $targetSet->getPropertySourceName($targetProperty);
+                $expression->pushStatement(
+                    $this->quoteSingleIdentifier($targetTable) . '.' .
+                    $this->quoteSingleIdentifier($targetColumn)
+                );
+            } else {
+                // Direct property (existing behavior)
+                $property = $properties[$propertyName];
+                $expression->pushStatement(
+                    $this->quoteSingleIdentifier($this->getPropertySourceName($property))
+                );
+            }
 
-            $expression->pushStatement($this->quoteSingleIdentifier($this->getPropertySourceName($property)));
             $expression->pushStatement($direction);
 
             if ($this->getDriver() === SQLEntitySet::PostgreSQL) {

src/Drivers/SQLEntitySet.php

@@ -360,15 +360,46 @@ public function getResultExpression(): SQLExpression
 
         $expression->pushStatement(sprintf("FROM %s", $this->quoteSingleIdentifier($this->getTable())));
 
+        $orderby = $this->generateOrderBy();
+
+        // Add LEFT JOINs for navigation properties referenced in $orderby
+        if (!empty($this->orderByNavigationJoins)) {
+            foreach ($this->orderByNavigationJoins as $joinInfo) {
+                $navigationProperty = $joinInfo['navigationProperty'];
+                $binding = $joinInfo['binding'];
+                $targetSet = $binding->getTarget();
+
+                $constraints = $navigationProperty->getConstraints();
+                foreach ($constraints as $constraint) {
+                    $localColumn = sprintf(
+                        '%s.%s',
+                        $this->quoteSingleIdentifier($this->getTable()),
+                        $this->quoteSingleIdentifier($this->getPropertySourceName($constraint->getProperty()))
+                    );
+                    $targetTable = $targetSet->getTable();
+                    $targetColumnRef = sprintf(
+                        '%s.%s',
+                        $this->quoteSingleIdentifier($targetTable),
+                        $this->quoteSingleIdentifier($targetSet->getPropertySourceName($constraint->getReferencedProperty()))
+                    );
+
+                    $expression->pushStatement(sprintf(
+                        'LEFT JOIN %s ON %s = %s',
+                        $this->quoteSingleIdentifier($targetTable),
+                        $localColumn,
+                        $targetColumnRef
+                    ));
+                }
+            }
+        }
+
         $where = $this->generateWhere();
 
         if ($where->hasStatement()) {
             $expression->pushStatement('WHERE');
             $expression->pushExpression($where);
         }
 
-        $orderby = $this->generateOrderBy();
-
         if ($orderby->hasStatement()) {
             $expression->pushStatement('ORDER BY');
             $expression->pushExpression($orderby);

src/EntitySet.php

@@ -1123,10 +1123,70 @@ protected function assertValidOrderBy(): void
             return $sort[0];
         }, $orderby->getSortOrders());
 
-        if ($diff = array_diff($sortProperties, $keys)) {
+        $invalidProperties = [];
+
+        foreach ($sortProperties as $propertyName) {
+            // Direct property — already valid
+            if (in_array($propertyName, $keys)) {
+                continue;
+            }
+
+            // Check for navigation property path (e.g., "Status/SortOrder")
+            if (str_contains($propertyName, '/')) {
+                $segments = explode('/', $propertyName);
+
+                if (count($segments) !== 2) {
+                    $invalidProperties[] = $propertyName;
+                    continue;
+                }
+
+                [$navPropertyName, $targetPropertyName] = $segments;
+
+                $navigationProperty = $this->getType()->getNavigationProperties()->get($navPropertyName);
+
+                if (!$navigationProperty) {
+                    $invalidProperties[] = $propertyName;
+                    continue;
+                }
+
+                if ($navigationProperty->isCollection()) {
+                    throw new BadRequestException(
+                        'invalid_orderby_collection_navigation',
+                        sprintf(
+                            'Cannot order by collection navigation property (%s)',
+                            $navPropertyName
+                        )
+                    );
+                }
+
+                $binding = $this->getBindingByNavigationProperty($navigationProperty);
+                if (!$binding) {
+                    $invalidProperties[] = $propertyName;
+                    continue;
+                }
+
+                $targetType = $binding->getTarget()->getType();
+                $targetProperty = $targetType->getProperty($targetPropertyName);
+
+                if (!$targetProperty) {
+                    $invalidProperties[] = $propertyName;
+                    continue;
+                }
+
+                // Valid navigation property path
+                continue;
+            }
+
+            $invalidProperties[] = $propertyName;
+        }
+
+        if ($invalidProperties) {
             throw new BadRequestException(
                 'invalid_sort_property',
-                sprintf('The orderby parameter specified properties (%s) that did not exist', join(',', $diff))
+                sprintf(
+                    'The orderby parameter specified properties (%s) that did not exist',
+                    join(',', $invalidProperties)
+                )
             );
         }
     }

tests/OrderBy/OrderBy.php

@@ -4,6 +4,7 @@
 
 namespace Flat3\Lodata\Tests\OrderBy;
 
+use Flat3\Lodata\Facades\Lodata;
 use Flat3\Lodata\Tests\Helpers\Request;
 use Flat3\Lodata\Tests\TestCase;
 
@@ -71,4 +72,52 @@ public function test_orderby_invalid_multiple()
                 ->orderby('name asc age desc')
         );
     }
+
+    public function test_orderby_navigation_property()
+    {
+        if (!Lodata::getEntitySet($this->entitySet)?->getType()->getNavigationProperties()->get('flight')) {
+            $this->markTestSkipped('Driver does not configure flight navigation property');
+        }
+
+        $this->assertJsonResponseSnapshot(
+            (new Request)
+                ->path($this->entitySetPath)
+                ->orderby('flight/origin asc')
+        );
+    }
+
+    public function test_orderby_navigation_property_desc()
+    {
+        if (!Lodata::getEntitySet($this->entitySet)?->getType()->getNavigationProperties()->get('flight')) {
+            $this->markTestSkipped('Driver does not configure flight navigation property');
+        }
+
+        $this->assertJsonResponseSnapshot(
+            (new Request)
+                ->path($this->entitySetPath)
+                ->orderby('flight/origin desc')
+        );
+    }
+
+    public function test_orderby_navigation_property_invalid()
+    {
+        $this->assertBadRequest(
+            (new Request)
+                ->path($this->entitySetPath)
+                ->orderby('nonexistent/foo asc')
+        );
+    }
+
+    public function test_orderby_navigation_property_collection()
+    {
+        if (!Lodata::getEntitySet($this->flightEntitySet)) {
+            $this->markTestSkipped('Driver does not configure flight entity set');
+        }
+
+        $this->assertBadRequest(
+            (new Request)
+                ->path($this->flightEntitySetPath)
+                ->orderby('passengers/name asc')
+        );
+    }
 }

tests/__snapshots__/OrderBy/CSVTest__test_orderby_navigation_property_invalid__1.json

@@ -0,0 +1,9 @@
+{
+    "error": {
+        "code": "invalid_sort_property",
+        "message": "The orderby parameter specified properties (nonexistent/foo) that did not exist",
+        "target": null,
+        "details": [],
+        "innererror": {}
+    }
+}

tests/__snapshots__/OrderBy/EloquentTest__test_orderby_navigation_property__1.json

@@ -0,0 +1,80 @@
+{
+    "@context": "http://localhost/odata/$metadata#Passengers",
+    "value": [
+        {
+            "id": 2,
+            "flight_id": null,
+            "name": "Beta",
+            "dob": "2001-02-02T05:05:05+00:00",
+            "age": 3,
+            "chips": false,
+            "dq": "2001-02-02",
+            "in_role": "P2DT5H5M5.2999999999884S",
+            "open_time": null,
+            "colour": null,
+            "sock_colours": null,
+            "emails": []
+        },
+        {
+            "id": 4,
+            "flight_id": null,
+            "name": "Delta",
+            "dob": null,
+            "age": null,
+            "chips": null,
+            "dq": null,
+            "in_role": "PT2M7S",
+            "open_time": null,
+            "colour": null,
+            "sock_colours": null,
+            "emails": []
+        },
+        {
+            "id": 5,
+            "flight_id": null,
+            "name": "Epsilon",
+            "dob": "2003-04-04T07:07:07+00:00",
+            "age": 2.4,
+            "chips": null,
+            "dq": "2003-04-04",
+            "in_role": "PT14M48.9S",
+            "open_time": "23:11:33.000000",
+            "colour": null,
+            "sock_colours": null,
+            "emails": []
+        },
+        {
+            "id": 1,
+            "flight_id": 1,
+            "name": "Alpha",
+            "dob": "2000-01-01T04:04:04+00:00",
+            "age": 4,
+            "chips": true,
+            "dq": "2000-01-01",
+            "in_role": "P1DT0S",
+            "open_time": "05:05:05.000000",
+            "colour": "Green",
+            "sock_colours": "Green,Blue",
+            "emails": [
+                "alpha@example.com",
+                "alpha@beta.com"
+            ]
+        },
+        {
+            "id": 3,
+            "flight_id": 1,
+            "name": "Gamma",
+            "dob": "2002-03-03T06:06:06+00:00",
+            "age": 2,
+            "chips": true,
+            "dq": "2002-03-03",
+            "in_role": "P4DT32M41S",
+            "open_time": "07:07:07.000000",
+            "colour": "Blue",
+            "sock_colours": "Red,Green,Blue",
+            "emails": [
+                "gamma@example.com"
+            ]
+        }
+    ]
+}

tests/__snapshots__/OrderBy/EloquentTest__test_orderby_navigation_property_collection__1.json

@@ -0,0 +1,9 @@
+{
+    "error": {
+        "code": "invalid_orderby_collection_navigation",
+        "message": "Cannot order by collection navigation property (passengers)",
+        "target": null,
+        "details": [],
+        "innererror": {}
+    }
+}