diff --git a/lib/Mapper.php b/lib/Mapper.php
index 7cf9595..2bf1e52 100644
--- a/lib/Mapper.php
+++ b/lib/Mapper.php
@@ -91,12 +91,14 @@ public function collectionClass()
 
     /**
      * Entity manager class for storing information and meta-data about entities
-     *
+     * @param string $entityName
      * @return \Spot\Entity\Manager
      */
-    public function entityManager()
+    public function entityManager($entityName = null)
     {
-        $entityName = $this->entity();
+        if (!$entityName) {
+            $entityName = $this->entity();
+        }
         if (!isset(self::$entityManager[$entityName])) {
             self::$entityManager[$entityName] = new Entity\Manager($entityName);
         }
diff --git a/lib/Query.php b/lib/Query.php
index c971d18..f80968b 100644
--- a/lib/Query.php
+++ b/lib/Query.php
@@ -2,8 +2,6 @@
 
 namespace Spot;
 
-use Doctrine\DBAL\Types\Type;
-
 /**
  * Query Object - Used to build adapter-independent queries PHP-style
  *
@@ -95,6 +93,13 @@ class Query implements \Countable, \IteratorAggregate, \ArrayAccess, \JsonSerial
      */
     protected static $_whereOperatorObjects = [];
 
+    /**
+     * For future use
+     * Store the type of relation with the selected mapper
+     * @var
+     */
+    protected $mapping;
+
     /**
      * Constructor Method
      *
@@ -209,6 +214,59 @@ public function select()
         return $this;
     }
 
+    /**
+     * Join (passthrough to DBAL QueryBuilder)
+     * @param string $fromAlias
+     * @param string $entityName
+     * @param string $alias
+     * @param null $condition
+     * @return $this
+     */
+    public function join($fromAlias, $entityName, $alias, $condition = null)
+    {
+        return $this->makeJoin(__FUNCTION__, $fromAlias, $entityName, $alias, $condition);
+
+    }
+    /**
+     * Inner Join (passthrough to DBAL QueryBuilder)
+     * @param string $fromAlias
+     * @param string $entityName
+     * @param string $alias
+     * @param null $condition
+     * @return $this
+     */
+    public function innerJoin($fromAlias, $entityName, $alias, $condition = null)
+    {
+        return $this->makeJoin(__FUNCTION__, $fromAlias, $entityName, $alias, $condition);
+
+    }
+    /**
+     * Left Join (passthrough to DBAL QueryBuilder)
+     * @param string $fromAlias
+     * @param string $entityName
+     * @param string $alias
+     * @param null $condition
+     * @return $this
+     */
+    public function leftJoin($fromAlias, $entityName, $alias, $condition = null)
+    {
+        return $this->makeJoin(__FUNCTION__, $fromAlias, $entityName, $alias, $condition);
+
+    }
+    /**
+     * Right Join (passthrough to DBAL QueryBuilder)
+     * @param string $fromAlias
+     * @param string $entityName
+     * @param string $alias
+     * @param null $condition
+     * @return $this
+     */
+    public function rightJoin($fromAlias, $entityName, $alias, $condition = null)
+    {
+        return $this->makeJoin(__FUNCTION__, $fromAlias, $entityName, $alias, $condition);
+
+    }
+
     /**
      * Delete (passthrough to DBAL QueryBuilder)
      *
@@ -347,10 +405,11 @@ public function whereSql($sql)
      *
      * @param array $where Array of conditions for this clause
      * @param bool $useAlias
+     * @param string $entityName
      * @return array SQL fragment strings for WHERE clause
      * @throws Exception
      */
-    private function parseWhereToSQLFragments(array $where, $useAlias = true)
+    private function parseWhereToSQLFragments(array $where, $useAlias = true, $entityName=null)
     {
         $builder = $this->builder();
 
@@ -383,9 +442,14 @@ private function parseWhereToSQLFragments(array $where, $useAlias = true)
 
             // Prefix column name with alias
             if ($useAlias === true) {
-                $col = $this->fieldWithAlias($col);
+                $col = $this->fieldWithAlias($col, true, $entityName);
             }
 
+            if ( $this->stringIsExistingField($entityName, $value) ){
+                $value = function () use ($value){
+                        return $value;
+                };
+            }
             $sqlFragments[] = $operatorCallable($builder, $col, $value);
         }
 
@@ -708,18 +772,25 @@ public function escapeIdentifier($identifier)
      * Get field name with table alias appended
      * @param string $field
      * @param bool $escaped
+     * @param string $entityName
      * @return string
      */
-    public function fieldWithAlias($field, $escaped = true)
+    public function fieldWithAlias($field, $escaped = true, $entityName = null)
     {
-        $fieldInfo = $this->_mapper->entityManager()->fields();
+        $fieldInfo = $this->_mapper->entityManager($entityName)->fields();
 
+        //extract table alias if present
+        list($field, $table) = $this->extractTableAndFieldFromString($field);
         // Determine real field name (column alias support)
         if (isset($fieldInfo[$field])) {
             $field = $fieldInfo[$field]['column'];
         }
 
-        $field = $this->_tableName . '.' . $field;
+        if (!$table) {
+            $table = $this->_mapper->entityManager($entityName)->table();
+        }
+
+        $field = $table . '.' . $field;
 
         return $escaped ? $this->escapeIdentifier($field) : $field;
     }
@@ -810,4 +881,102 @@ public function __call($method, $args)
             throw new \BadMethodCallException("Method '" . __CLASS__ . "::" . $method . "' not found");
         }
     }
+
+    /**
+     * Store the mapping of tables and mapper
+     * @param string $type
+     * @param array $data
+     */
+    private function addMapping($type, array $data)
+    {
+        $type = (string)$type;
+        $this->mapping[$type] = $data;
+    }
+
+    /**
+     * Add a join of type $type
+     * @param string $type
+     * @param string $fromAlias
+     * @param string $entityName
+     * @param string $alias
+     * @param string $condition
+     * @return $this
+     */
+    public function makeJoin($type, $fromAlias, $entityName, $alias, $condition)
+    {
+        $joinTable = $this->mapper()->getMapper($entityName)->table();
+//        $conditionString = (string)$condition;
+
+        $this->addMapping(
+            'join',
+            array(
+                $fromAlias => array(
+                    'joinTable' => $joinTable,
+                    'joinAlias' => $alias,
+                    'joinEntity' => $entityName,
+
+                ),
+            )
+        );
+//        $testCondition = explode('=', $condition);
+        $conditionString = implode(' AND ', $this->parseWhereToSQLFragments($condition, true, $entityName));
+//        $conditionString = implode(' =', $condition);
+        //@FIXME: now parameters are double escaped, because the initial are double escaped also :(
+        $this->builder()->$type(
+            $this->escapeIdentifier($fromAlias),
+            $this->escapeIdentifier($joinTable),
+            $this->escapeIdentifier($alias),
+            $conditionString
+        );
+
+        return $this;
+    }
+
+    /**
+     * Extract data from string, for strings which contains "point"
+     * @Example: table.field
+     * @param $string
+     * @return array
+     */
+    public function extractTableAndFieldFromString($string)
+    {
+        $pointPosition = strpos($string, '.');
+        if ($pointPosition !== false) {
+            $table = substr($string, 0, $pointPosition);
+            $field = substr($string, $pointPosition + 1);
+        } else {
+            $table = null;
+            $field = $string;
+        }
+
+        return [$field, $table];
+
+    }
+
+    /**
+     * Determine if the value is a existing field
+     * @param string $entityName
+     * @param string $value
+     * @return string
+     */
+    public function stringIsExistingField($entityName, $value)
+    {
+        $field = '';
+        if (is_array($value)) {
+            return $field;
+        }
+        $fieldInfo = array_merge(
+            $this->_mapper->entityManager($entityName)->fields(),
+            $this->_mapper->entityManager()->fields()
+        );
+        $field = null;
+        //extract table alias if present
+        list($extractedField, $table) = $this->extractTableAndFieldFromString($value);
+        // Determine real field name (column alias support)
+        if (isset($fieldInfo[$extractedField])) {
+            $field = $fieldInfo[$extractedField]['column'];
+        }
+
+        return $field;
+    }
 }
diff --git a/lib/Query/Operator/Equals.php b/lib/Query/Operator/Equals.php
index 4548b1b..8ea1a89 100644
--- a/lib/Query/Operator/Equals.php
+++ b/lib/Query/Operator/Equals.php
@@ -28,6 +28,10 @@ public function __invoke(QueryBuilder $builder, $column, $value)
             return $column . ' IS NULL';
         }
 
+        if ($value instanceof \Closure) {
+            return $column . ' = ' . $value();
+        }
+
         return $column . ' = ' . $builder->createPositionalParameter($value);
     }
 }
diff --git a/lib/Query/Operator/FullText.php b/lib/Query/Operator/FullText.php
index 0ea6661..c069292 100644
--- a/lib/Query/Operator/FullText.php
+++ b/lib/Query/Operator/FullText.php
@@ -17,6 +17,10 @@ class FullText
      */
     public function __invoke(QueryBuilder $builder, $column, $value)
     {
+        if ($value instanceof \Closure) {
+            return $column . ' = ' . $value();
+        }
+
         return 'MATCH(' . $column . ') AGAINST (' . $builder->createPositionalParameter($value) . ')';
     }
 }
diff --git a/lib/Query/Operator/FullTextBoolean.php b/lib/Query/Operator/FullTextBoolean.php
index 2b5e1b5..383ceb1 100644
--- a/lib/Query/Operator/FullTextBoolean.php
+++ b/lib/Query/Operator/FullTextBoolean.php
@@ -17,6 +17,10 @@ class FullTextBoolean
      */
     public function __invoke(QueryBuilder $builder, $column, $value)
     {
+        if ($value instanceof \Closure) {
+            return $column . ' = ' . $value();
+        }
+
         return 'MATCH(' . $column . ') AGAINST (' . $builder->createPositionalParameter($value) . ' IN BOOLEAN MODE)';
     }
 }
diff --git a/lib/Query/Operator/GreaterThan.php b/lib/Query/Operator/GreaterThan.php
index af9e8be..1dd7799 100644
--- a/lib/Query/Operator/GreaterThan.php
+++ b/lib/Query/Operator/GreaterThan.php
@@ -17,6 +17,10 @@ class GreaterThan
      */
     public function __invoke(QueryBuilder $builder, $column, $value)
     {
+        if ($value instanceof \Closure) {
+            return $column . ' = ' . $value();
+        }
+
         return $column . ' > ' . $builder->createPositionalParameter($value);
     }
 }
diff --git a/lib/Query/Operator/GreaterThanOrEqual.php b/lib/Query/Operator/GreaterThanOrEqual.php
index 8003674..db9e522 100644
--- a/lib/Query/Operator/GreaterThanOrEqual.php
+++ b/lib/Query/Operator/GreaterThanOrEqual.php
@@ -17,6 +17,10 @@ class GreaterThanOrEqual
      */
     public function __invoke(QueryBuilder $builder, $column, $value)
     {
+        if ($value instanceof \Closure) {
+            return $column . ' = ' . $value();
+        }
+
         return $column . ' >= ' . $builder->createPositionalParameter($value);
     }
 }
diff --git a/lib/Query/Operator/In.php b/lib/Query/Operator/In.php
index 1985044..05c9ac9 100644
--- a/lib/Query/Operator/In.php
+++ b/lib/Query/Operator/In.php
@@ -24,6 +24,10 @@ public function __invoke(QueryBuilder $builder, $column, $value)
             throw new Exception("Use of IN operator expects value to be array. Got " . gettype($value) . ".");
         }
 
+        if ($value instanceof \Closure) {
+            return $column . ' = ' . $value();
+        }
+
         return $column . ' IN (' . $builder->createPositionalParameter($value, Connection::PARAM_STR_ARRAY) . ')';
     }
 }
diff --git a/lib/Query/Operator/LessThan.php b/lib/Query/Operator/LessThan.php
index a888704..e57a7c7 100644
--- a/lib/Query/Operator/LessThan.php
+++ b/lib/Query/Operator/LessThan.php
@@ -17,6 +17,10 @@ class LessThan
      */
     public function __invoke(QueryBuilder $builder, $column, $value)
     {
+        if ($value instanceof \Closure) {
+            return $column . ' < ' . $value();
+        }
+
         return $column . ' < ' . $builder->createPositionalParameter($value);
     }
 }
diff --git a/lib/Query/Operator/LessThanOrEqual.php b/lib/Query/Operator/LessThanOrEqual.php
index 59b0789..1828504 100644
--- a/lib/Query/Operator/LessThanOrEqual.php
+++ b/lib/Query/Operator/LessThanOrEqual.php
@@ -17,6 +17,10 @@ class LessThanOrEqual
      */
     public function __invoke(QueryBuilder $builder, $column, $value)
     {
+        if ($value instanceof \Closure) {
+            return $column . ' <= ' . $value();
+        }
+
         return $column . ' <= ' . $builder->createPositionalParameter($value);
     }
 }
diff --git a/lib/Query/Operator/Like.php b/lib/Query/Operator/Like.php
index d2c1fc5..019c68a 100644
--- a/lib/Query/Operator/Like.php
+++ b/lib/Query/Operator/Like.php
@@ -17,6 +17,10 @@ class Like
      */
     public function __invoke(QueryBuilder $builder, $column, $value)
     {
+        if ($value instanceof \Closure) {
+            return $column . ' = ' . $value();
+        }
+
         return $column . ' LIKE ' . $builder->createPositionalParameter($value);
     }
 }
diff --git a/lib/Query/Operator/Not.php b/lib/Query/Operator/Not.php
index b0ce871..0044ad8 100644
--- a/lib/Query/Operator/Not.php
+++ b/lib/Query/Operator/Not.php
@@ -21,13 +21,18 @@ class Not
     public function __invoke(QueryBuilder $builder, $column, $value)
     {
         if (is_array($value) && !empty($value)) {
-            return $column . ' NOT IN (' . $builder->createPositionalParameter($value, Connection::PARAM_STR_ARRAY) . ')';
+            return $column . ' NOT IN (' . $builder->createPositionalParameter($value,
+                Connection::PARAM_STR_ARRAY) . ')';
         }
 
         if ($value === null || (is_array($value) && empty($value))) {
             return $column . ' IS NOT NULL';
         }
 
+        if ($value instanceof \Closure) {
+            return $column . ' = ' . $value();
+        }
+
         return $column . ' != ' . $builder->createPositionalParameter($value);
     }
 }
diff --git a/lib/Query/Operator/RegExp.php b/lib/Query/Operator/RegExp.php
index e33cfc2..e66eb39 100644
--- a/lib/Query/Operator/RegExp.php
+++ b/lib/Query/Operator/RegExp.php
@@ -17,6 +17,10 @@ class RegExp
      */
     public function __invoke(QueryBuilder $builder, $column, $value)
     {
+        if ($value instanceof \Closure) {
+            return $column . ' = ' . $value();
+        }
+
         return $column . ' REGEXP ' . $builder->createPositionalParameter($value);
     }
 }
diff --git a/test b/test
new file mode 100644
index 0000000..9daeafb
--- /dev/null
+++ b/test
@@ -0,0 +1 @@
+test
diff --git a/tests/Mapper.php b/tests/Mapper.php
index 4bd1f3e..af20423 100644
--- a/tests/Mapper.php
+++ b/tests/Mapper.php
@@ -20,4 +20,67 @@ public function testGetCustomEntityMapper()
         $query = $mapper->testQuery();
         $this->assertInstanceOf('Spot\Query', $query);
     }
+
+    /**
+     * entityManager() return the current entity if $entityName is empty
+     */
+    public function testEntityManagerReturnTheCurrentEntityIfEntityNameIsEmpty()
+    {
+        $mapper = test_spot_mapper('SpotTest\Entity\NotNullOverride');
+        $manager = $mapper->entityManager();
+        $currentEntity = $mapper->entity();
+        $reflection = new \ReflectionClass(get_class($manager));
+        $privateProperty = $reflection->getProperty('entityName');
+        $privateProperty->setAccessible(true);
+        $privateValue = $privateProperty->getValue($manager);
+        $this->assertEquals($currentEntity, $privateValue);
+    }
+
+
+    /**
+     * entityManager() return the same entity if we passed as parameter
+     */
+    public function testEntityManagerReturnTheSameEntityIfWePassedAsParameter()
+    {
+        $mapper = test_spot_mapper('SpotTest\Entity\NotNullOverride');
+        test_spot_mapper('\SpotTest\Entity\Author');
+        $manager = $mapper->entityManager('\SpotTest\Entity\Author');
+        $currentEntity = $mapper->entity();
+        $reflection = new \ReflectionClass(get_class($manager));
+        $privateProperty = $reflection->getProperty('entityName');
+        $privateProperty->setAccessible(true);
+        $privateValue = $privateProperty->getValue($manager);
+        $this->assertNotEquals($currentEntity, $privateValue);
+    }
+
+
+    /**
+     * entityManager() return will return different entity from current entity if we passed as parameter
+     */
+    public function testEntityManagerReturnWillReturnDifferentEntityFromCurrentEntityIfWePassedAsParameter()
+    {
+        $mapper = test_spot_mapper('SpotTest\Entity\NotNullOverride');
+        test_spot_mapper('\SpotTest\Entity\Author');
+        $manager = $mapper->entityManager('\SpotTest\Entity\Author');
+        $reflection = new \ReflectionClass(get_class($manager));
+        $privateProperty = $reflection->getProperty('entityName');
+        $privateProperty->setAccessible(true);
+        $privateValue = $privateProperty->getValue($manager);
+        $this->assertEquals('\SpotTest\Entity\Author', $privateValue);
+    }
+
+
+    /**
+     * entityManager() always return instance of Entity\Manager
+     */
+    public function testEntityManagerAlwaysReturnInstanceOfEntityManager()
+    {
+        $mapper = test_spot_mapper('\SpotTest\Entity\NotNullOverride');
+        test_spot_mapper('\SpotTest\Entity\Author');
+        $manager = $mapper->entityManager('\SpotTest\Entity\Author');
+        $managerCurrent = $mapper->entityManager();
+        $this->assertInstanceOf('\Spot\Entity\Manager', $manager);
+        $this->assertInstanceOf('\Spot\Entity\Manager', $managerCurrent);
+    }
+
 }