diff --git a/lib/Doctrine/ORM/Query/SqlWalker.php b/lib/Doctrine/ORM/Query/SqlWalker.php
index 52e73585e..3de86103a 100644
--- a/lib/Doctrine/ORM/Query/SqlWalker.php
+++ b/lib/Doctrine/ORM/Query/SqlWalker.php
@@ -1620,7 +1620,7 @@ public function walkArithmeticExpression($arithmeticExpr)
     {
         return ($arithmeticExpr->isSimpleArithmeticExpression())
         	? $this->walkSimpleArithmeticExpression($arithmeticExpr->simpleArithmeticExpression)
-        	: $this->walkSubselect($arithmeticExpr->subselect);
+        	: '(' . $this->walkSubselect($arithmeticExpr->subselect) . ')';
     }
 
     /**
diff --git a/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php b/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php
index 716182ac1..5de5d0349 100644
--- a/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php
+++ b/tests/Doctrine/Tests/ORM/Query/SelectSqlGenerationTest.php
@@ -325,6 +325,17 @@ public function testSupportsExistsExpressionInWherePartWithCorrelatedSubquery()
         );
     }
 
+    /**
+     * @group DDC-593
+     */
+    public function testSubqueriesInComparisonExpression()
+    {
+        $this->assertSqlGeneration(
+            'SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u WHERE (u.id >= (SELECT u2.id FROM Doctrine\Tests\Models\CMS\CmsUser u2 WHERE u2.name = :name)) AND (u.id <= (SELECT u3.id FROM Doctrine\Tests\Models\CMS\CmsUser u3 WHERE u3.name = :name))',
+            'SELECT c0_.id AS id0, c0_.status AS status1, c0_.username AS username2, c0_.name AS name3 FROM cms_users c0_ WHERE (c0_.id >= (SELECT c1_.id FROM cms_users c1_ WHERE c1_.name = ?)) AND (c0_.id <= (SELECT c2_.id FROM cms_users c2_ WHERE c2_.name = ?))'
+        );
+    }
+
     public function testSupportsMemberOfExpression()
     {
         // "Get all users who have $phone as a phonenumber." (*cough* doesnt really make sense...)