diff --git a/lib/Doctrine/ORM/Query/AST/Functions/DateAddFunction.php b/lib/Doctrine/ORM/Query/AST/Functions/DateAddFunction.php
index 1c3817fe2..d78cd976a 100644
--- a/lib/Doctrine/ORM/Query/AST/Functions/DateAddFunction.php
+++ b/lib/Doctrine/ORM/Query/AST/Functions/DateAddFunction.php
@@ -45,6 +45,11 @@ class DateAddFunction extends FunctionNode
     public function getSql(SqlWalker $sqlWalker)
     {
         switch (strtolower($this->unit->value)) {
+            case 'hour':
+                return $sqlWalker->getConnection()->getDatabasePlatform()->getDateAddHourExpression(
+                    $this->firstDateExpression->dispatch($sqlWalker),
+                    $this->intervalExpression->dispatch($sqlWalker)
+                );
             case 'day':
                 return $sqlWalker->getConnection()->getDatabasePlatform()->getDateAddDaysExpression(
                     $this->firstDateExpression->dispatch($sqlWalker),
@@ -59,7 +64,7 @@ class DateAddFunction extends FunctionNode
 
             default:
                 throw QueryException::semanticalError(
-                    'DATE_ADD() only supports units of type day and month.'
+                    'DATE_ADD() only supports units of type hour, day and month.'
                 );
         }
     }
diff --git a/lib/Doctrine/ORM/Query/AST/Functions/DateSubFunction.php b/lib/Doctrine/ORM/Query/AST/Functions/DateSubFunction.php
index 35add0ed6..bcd994ba9 100644
--- a/lib/Doctrine/ORM/Query/AST/Functions/DateSubFunction.php
+++ b/lib/Doctrine/ORM/Query/AST/Functions/DateSubFunction.php
@@ -39,6 +39,11 @@ class DateSubFunction extends DateAddFunction
     public function getSql(SqlWalker $sqlWalker)
     {
         switch (strtolower($this->unit->value)) {
+            case 'hour':
+                return $sqlWalker->getConnection()->getDatabasePlatform()->getDateSubHourExpression(
+                    $this->firstDateExpression->dispatch($sqlWalker),
+                    $this->intervalExpression->dispatch($sqlWalker)
+                );
             case 'day':
                 return $sqlWalker->getConnection()->getDatabasePlatform()->getDateSubDaysExpression(
                     $this->firstDateExpression->dispatch($sqlWalker),