diff --git a/lib/Doctrine/ORM/Query/Parser.php b/lib/Doctrine/ORM/Query/Parser.php
index 0233e4c5e..4d097b5ff 100644
--- a/lib/Doctrine/ORM/Query/Parser.php
+++ b/lib/Doctrine/ORM/Query/Parser.php
@@ -1339,12 +1339,37 @@ class Parser
      */
     public function OrderByItem()
     {
-        $type = 'ASC';
-
         // We need to check if we are in a ResultVariable or StateFieldPathExpression
         $glimpse = $this->_lexer->glimpse();
-        $expr    = ($glimpse['type'] != Lexer::T_DOT) ? $this->ResultVariable() : $this->SingleValuedPathExpression();
 
+        switch (true) {
+            case ($glimpse['type'] === Lexer::T_DOT):
+                $expr = $this->SingleValuedPathExpression();
+                break;
+
+            case ($this->_isFunction()):
+                $this->_lexer->peek(); // "("
+                
+                // SUM(u.id) + COUNT(u.id)
+                if ($this->_isMathOperator($this->_peekBeyondClosingParenthesis())) {
+                    $expr = $this->ScalarExpression();
+                    break;
+                }
+                // COUNT(u.id)
+                if ($this->_isAggregateFunction($this->_lexer->lookahead['type'])) {
+                    $expr = $this->AggregateExpression();
+                    break;
+                }
+                // IDENTITY(u)
+                $expr = $this->FunctionDeclaration();
+                break;
+
+            default:
+                $expr = $this->ResultVariable();
+                break;
+        }
+
+        $type = 'ASC';
         $item = new AST\OrderByItem($expr);
 
         switch (true) {
@@ -2166,10 +2191,10 @@ class Parser
         if (in_array($peek['value'], array("=",  "<", "<=", "<>", ">", ">=", "!=")) ||
             in_array($peek['type'], array(Lexer::T_NOT, Lexer::T_BETWEEN, Lexer::T_LIKE, Lexer::T_IN, Lexer::T_IS, Lexer::T_EXISTS)) ||
             $this->_isMathOperator($peek)) {
-            $condPrimary->simpleConditionalExpression = $this->SimpleConditionalExpression();
+                $condPrimary->simpleConditionalExpression = $this->SimpleConditionalExpression();
 
-            return $condPrimary;
-        }
+                return $condPrimary;
+            }
 
         $this->match(Lexer::T_OPEN_PARENTHESIS);
         $condPrimary->conditionalExpression = $this->ConditionalExpression();
diff --git a/lib/Doctrine/ORM/Query/SqlWalker.php b/lib/Doctrine/ORM/Query/SqlWalker.php
index b04d6e8d3..8426dc124 100644
--- a/lib/Doctrine/ORM/Query/SqlWalker.php
+++ b/lib/Doctrine/ORM/Query/SqlWalker.php
@@ -780,9 +780,18 @@ class SqlWalker implements TreeWalker
     public function walkOrderByItem($orderByItem)
     {
         $expr = $orderByItem->expression;
-        $sql  = ($expr instanceof AST\PathExpression)
-            ? $this->walkPathExpression($expr)
-            : $this->walkResultVariable($this->_queryComponents[$expr]['token']['value']);
+
+        switch (true) {
+            case ($expr instanceof AST\PathExpression):
+            case ($expr instanceof AST\AggregateExpression):
+            case ($expr instanceof AST\Functions\FunctionNode):
+            case ($expr instanceof AST\SimpleArithmeticExpression):
+                $sql = $expr->dispatch($this);
+                break;
+            default:
+                $sql = $this->walkResultVariable($this->_queryComponents[$expr]['token']['value']);
+                break;
+        }
 
         return $sql . ' ' . strtoupper($orderByItem->type);
     }
diff --git a/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php b/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php
index 5b750462c..e77fa6447 100644
--- a/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php
+++ b/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php
@@ -1571,6 +1571,54 @@ class SelectSqlGenerationTest extends \Doctrine\Tests\OrmTestCase
             "SELECT c0_.id AS id0, c0_.completed AS completed1, c0_.fixPrice AS fixPrice2, c1_.id AS id3, c1_.completed AS completed4, c1_.hoursWorked AS hoursWorked5, c1_.pricePerHour AS pricePerHour6, c1_.maxPrice AS maxPrice7, c0_.discr AS discr8, c1_.discr AS discr9 FROM company_contracts c0_, company_contracts c1_ WHERE (c0_.discr IN ('fix') AND c1_.discr IN ('flexible', 'flexultra'))"
         );
     }
+
+    /**
+     * @group DDC-775
+     */
+    public function testOrderByClauseSupportFunctions()
+    {
+        $this->assertSqlGeneration(
+            'SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u ORDER BY TRIM(u.name)',
+            'SELECT c0_.id AS id0, c0_.status AS status1, c0_.username AS username2, c0_.name AS name3 FROM cms_users c0_ ORDER BY TRIM(c0_.name) ASC'
+        );
+
+        $this->assertSqlGeneration(
+            'SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u ORDER BY IDENTITY(u.email)',
+            'SELECT c0_.id AS id0, c0_.status AS status1, c0_.username AS username2, c0_.name AS name3 FROM cms_users c0_ ORDER BY c0_.email_id ASC'
+        );
+
+        $this->assertSqlGeneration(
+            'SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u ORDER BY TRIM(IDENTITY(u.email))',
+            'SELECT c0_.id AS id0, c0_.status AS status1, c0_.username AS username2, c0_.name AS name3 FROM cms_users c0_ ORDER BY TRIM(c0_.email_id) ASC'
+        );
+
+        $this->assertSqlGeneration(
+            'SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u ORDER BY SUM(u.id)',
+            'SELECT c0_.id AS id0, c0_.status AS status1, c0_.username AS username2, c0_.name AS name3 FROM cms_users c0_ ORDER BY SUM(c0_.id) ASC'
+        );
+
+        $this->assertSqlGeneration(
+            'SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u ORDER BY SUM(u.id) + COUNT(u.email)',
+            'SELECT c0_.id AS id0, c0_.status AS status1, c0_.username AS username2, c0_.name AS name3 FROM cms_users c0_ ORDER BY SUM(c0_.id) + COUNT(c0_.email_id) ASC'
+        );
+    }
+
+    /**
+     * @group DDC-775
+     */
+    public function testOrderByClauseSupportNullIfAndCoalesce()
+    {
+        $this->markTestIncomplete();
+        $this->assertSqlGeneration(
+            'SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u ORDER BY NULLIF(u.name, u.username)',
+            'SELECT c0_.id AS id0, c0_.status AS status1, c0_.username AS username2, c0_.name AS name3 FROM cms_users c0_ ORDER BY NULLIF(c0_.name, c0_.username) ASC'
+        );
+
+        $this->assertSqlGeneration(
+            'SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u ORDER BY NULLIF(u.name, u.username)',
+            'SELECT c0_.id AS id0, c0_.status AS status1, c0_.username AS username2, c0_.name AS name3 FROM cms_users c0_ ORDER BY COALESCE(NULLIF(u.name, \'\'), u.username) ASC'
+        );
+    }
 }