diff --git a/src/Query/Mysql/SubstringIndex.php b/src/Query/Mysql/SubstringIndex.php
index 4983cc11..3f722128 100644
--- a/src/Query/Mysql/SubstringIndex.php
+++ b/src/Query/Mysql/SubstringIndex.php
@@ -2,20 +2,26 @@
 
 namespace DoctrineExtensions\Query\Mysql;
 
-use Doctrine\ORM\Query\AST\Functions\FunctionNode,
-    Doctrine\ORM\Query\Lexer;
+use  Doctrine\ORM\Query\AST\Functions\FunctionNode;
+use  Doctrine\ORM\Query\Lexer;
+use  Doctrine\ORM\Query\Parser;
+use  Doctrine\ORM\Query\SqlWalker;
 
 /**
+ * Class SubstringIndex
+ * @package DoctrineExtensions\Query\Mysql
  * @author Vas N <phpvas@gmail.com>
  */
-
 class SubstringIndex extends FunctionNode
 {
     public $string = null;
     public $delimiter = null;
     public $count = null;
 
-    public function parse(\Doctrine\ORM\Query\Parser $parser)
+    /**
+     * @param \Doctrine\ORM\Query\Parser $parser
+     */
+    public function parse(Parser $parser)
     {
         $parser->match(Lexer::T_IDENTIFIER);
         $parser->match(Lexer::T_OPEN_PARENTHESIS);
@@ -23,16 +29,20 @@ public function parse(\Doctrine\ORM\Query\Parser $parser)
         $parser->match(Lexer::T_COMMA);
         $this->delimiter = $parser->ArithmeticPrimary();
         $parser->match(Lexer::T_COMMA);
-        $this->count = $parser->ArithmeticPrimary();
+        $this->count = $parser->ArithmeticExpression();
         $parser->match(Lexer::T_CLOSE_PARENTHESIS);
     }
 
-    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
+    /**
+     * @param \Doctrine\ORM\Query\SqlWalker $sqlWalker
+     * @return string
+     */
+    public function getSql(SqlWalker $sqlWalker)
     {
-        return 'SUBSTRING_INDEX(' .
-            $this->string->dispatch($sqlWalker) . ', ' .
-            $this->delimiter->dispatch($sqlWalker) . ', ' .
-            $this->count->dispatch($sqlWalker) .
-        ')';
+        return sprintf('SUBSTRING_INDEX(%s, %s, %s)',
+            $this->string->dispatch($sqlWalker),
+            $this->delimiter->dispatch($sqlWalker),
+            $this->count->dispatch($sqlWalker)
+        );
     }
 }
diff --git a/tests/Query/Mysql/StringTest.php b/tests/Query/Mysql/StringTest.php
index 5c3361d7..2e656617 100644
--- a/tests/Query/Mysql/StringTest.php
+++ b/tests/Query/Mysql/StringTest.php
@@ -84,14 +84,21 @@ public function testSoundex()
         );
     }
 
+  /**
+   * Test cases for MYSQL SUBSTRING_INDEX function.
+   */
     public function testSubstringIndex()
     {
-        $q = $this->entityManager->createQuery("SELECT SUBSTRING_INDEX('www.mysql.com', '.', 2) from DoctrineExtensions\Tests\Entities\Blank");
-
-        $this->assertEquals(
-            "SELECT SUBSTRING_INDEX('www.mysql.com', '.', 2) AS sclr_0 FROM Blank b0_",
-            $q->getSql()
-        );
+      $q = $this->entityManager->createQuery("SELECT SUBSTRING_INDEX('www.mysql.com', '.', 2) from DoctrineExtensions\Tests\Entities\Blank");
+      $this->assertEquals("SELECT SUBSTRING_INDEX('www.mysql.com', '.', 2) AS sclr_0 FROM Blank b0_", $q->getSql());
+      $q = $this->entityManager->createQuery("SELECT SUBSTRING_INDEX('www.mysql.com', '.', -2) from DoctrineExtensions\Tests\Entities\Blank");
+      $this->assertEquals("SELECT SUBSTRING_INDEX('www.mysql.com', '.', -2) AS sclr_0 FROM Blank b0_", $q->getSql());
+      $q = $this->entityManager->createQuery("SELECT SUBSTRING_INDEX('www.mysql.com', '.', '-2') from DoctrineExtensions\Tests\Entities\Blank");
+      $this->assertEquals("SELECT SUBSTRING_INDEX('www.mysql.com', '.', '-2') AS sclr_0 FROM Blank b0_", $q->getSql());
+      $q = $this->entityManager->createQuery("SELECT SUBSTRING_INDEX(b.id, '', '4') from DoctrineExtensions\Tests\Entities\Blank b");
+      $this->assertEquals("SELECT SUBSTRING_INDEX(b0_.id, '', '4') AS sclr_0 FROM Blank b0_", $q->getSql());
+      $q = $this->entityManager->createQuery("SELECT SUBSTRING_INDEX(b.id, '', -1) from DoctrineExtensions\Tests\Entities\Blank b");
+      $this->assertEquals("SELECT SUBSTRING_INDEX(b0_.id, '', -1) AS sclr_0 FROM Blank b0_", $q->getSql());
     }
 
     /**
@@ -99,10 +106,10 @@ public function testSubstringIndex()
      */
     public function testLeast()
     {
-        $q = $this->entityManager->createQuery("SELECT LEAST(10,1,4,0.4,0.003) AS lest FROM DoctrineExtensions\Tests\Entities\Blank b");
+        $q = $this->entityManager->createQuery("SELECT LEAST(10,1,-4,0.4,0.003) AS lest FROM DoctrineExtensions\Tests\Entities\Blank b");
 
         $this->assertEquals(
-            'SELECT LEAST(10, 1, 4, 0.4, 0.003) AS sclr_0 FROM Blank b0_',
+            'SELECT LEAST(10, 1, -4, 0.4, 0.003) AS sclr_0 FROM Blank b0_',
             $q->getSql()
         );