diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/AST/KeyValue/RangeExpression.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/AST/KeyValue/RangeExpression.php
index af6951a2ab..17cd9a5356 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/AST/KeyValue/RangeExpression.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/AST/KeyValue/RangeExpression.php
@@ -20,22 +20,22 @@ class RangeExpression extends Node
 
     public static function lessThan(Key $key, $bound)
     {
-        return new self($key, $bound, false);
+        return new self($key, null, false, $bound, false);
     }
 
     public static function lessThanOrEqual(Key $key, $bound)
     {
-        return new self($key, $bound, true);
+        return new self($key, null, false, $bound, true);
     }
 
     public static function greaterThan(Key $key, $bound)
     {
-        return new self($key, null, false, $bound, false);
+        return new self($key, $bound, false);
     }
 
     public static function greaterThanOrEqual(Key $key, $bound)
     {
-        return new self($key, null, false, $bound, true);
+        return new self($key, $bound, true);
     }
 
     public function __construct(Key $key, $lb, $li = false, $hb = null, $hi = false)
@@ -57,17 +57,17 @@ class RangeExpression extends Node
         if ($this->lower_bound !== null) {
             $this->assertValueCompatible($this->lower_bound, $context);
             if ($this->lower_inclusive) {
-                $params['lte'] = $this->lower_bound;
+                $params['gte'] = $this->lower_bound;
             } else {
-                $params['lt'] = $this->lower_bound;
+                $params['gt'] = $this->lower_bound;
             }
         }
         if ($this->higher_bound !== null) {
             $this->assertValueCompatible($this->higher_bound, $context);
             if ($this->higher_inclusive) {
-                $params['gte'] = $this->higher_bound;
+                $params['lte'] = $this->higher_bound;
             } else {
-                $params['gt'] = $this->higher_bound;
+                $params['lt'] = $this->higher_bound;
             }
         }
 
@@ -98,16 +98,16 @@ class RangeExpression extends Node
         $string = '';
         if ($this->lower_bound !== null) {
             if ($this->lower_inclusive) {
-                $string .= sprintf(' lte="%s"', $this->lower_bound);
+                $string .= sprintf(' gte="%s"', $this->lower_bound);
             } else {
-                $string .= sprintf(' lt="%s"', $this->lower_bound);
+                $string .= sprintf(' gt="%s"', $this->lower_bound);
             }
         }
         if ($this->higher_bound !== null) {
             if ($this->higher_inclusive) {
-                $string .= sprintf(' gte="%s"', $this->higher_bound);
+                $string .= sprintf(' lte="%s"', $this->higher_bound);
             } else {
-                $string .= sprintf(' gt="%s"', $this->higher_bound);
+                $string .= sprintf(' lt="%s"', $this->higher_bound);
             }
         }
 
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryHelper.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryHelper.php
index 9d652f86c7..a8c80d9f99 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryHelper.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryHelper.php
@@ -2,6 +2,7 @@
 
 namespace Alchemy\Phrasea\SearchEngine\Elastic\Search;
 
+use Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
 use Alchemy\Phrasea\SearchEngine\Elastic\Structure\Field;
 
 class QueryHelper
@@ -107,4 +108,42 @@ class QueryHelper
             return $query;
         }
     }
+
+    public static function getRangeFromDateString($string)
+    {
+        $formats = ['Y/m/d', 'Y/m', 'Y'];
+        $deltas = ['+1 day', '+1 month', '+1 year'];
+        $to = null;
+        while ($format = array_pop($formats)) {
+            $delta = array_pop($deltas);
+            $from = date_create_from_format($format, $string);
+            if ($from !== false) {
+                // Rewind to start of range
+                $month = 1;
+                $day = 1;
+                switch ($format) {
+                    case 'Y/m/d':
+                        $day = (int) $from->format('d');
+                    case 'Y/m':
+                        $month = (int) $from->format('m');
+                    case 'Y':
+                        $year = (int) $from->format('Y');
+                }
+                date_date_set($from, $year, $month, $day);
+                date_time_set($from, 0, 0, 0);
+                // Create end of the the range
+                $to = date_modify(clone $from, $delta);
+                break;
+            }
+        }
+
+        if (!$from || !$to) {
+            throw new \InvalidArgumentException(sprintf('Invalid date "%s".', $string));
+        }
+
+        return [
+            'from' => $from->format(Mapping::DATE_FORMAT_CAPTION_PHP),
+            'to'   => $to->format(Mapping::DATE_FORMAT_CAPTION_PHP)
+        ];
+    }
 }
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryVisitor.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryVisitor.php
index 17955e1589..0c0edaec9b 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryVisitor.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/QueryVisitor.php
@@ -4,6 +4,7 @@ namespace Alchemy\Phrasea\SearchEngine\Elastic\Search;
 
 use Alchemy\Phrasea\SearchEngine\Elastic\AST;
 use Alchemy\Phrasea\SearchEngine\Elastic\Exception\Exception;
+use Alchemy\Phrasea\SearchEngine\Elastic\Search\QueryHelper;
 use Hoa\Compiler\Llk\TreeNode;
 use Hoa\Visitor\Element;
 use Hoa\Visitor\Visit;
@@ -176,10 +177,29 @@ class QueryVisitor implements Visit
     private function visitEqualNode(TreeNode $node)
     {
         return $this->handleBinaryExpression($node, function($left, $right) {
+            if ($this->isDateKey($left)) {
+                try {
+                    // Try to create a range for incomplete dates
+                    $range = QueryHelper::getRangeFromDateString($right);
+                    return new AST\KeyValue\RangeExpression(
+                        $left,
+                        $range['from'], true,
+                        $range['to'], false
+                    );
+                } catch (\InvalidArgumentException $e) {
+                    // Fall back to equal expression
+                }
+            }
+
             return new AST\KeyValue\EqualExpression($left, $right);
         });
     }
 
+    private function isDateKey(AST\KeyValue\Key $key)
+    {
+        return $key instanceof AST\KeyValue\TimestampKey;
+    }
+
     private function visitTerm(Element $element)
     {
         $words = array();