Fix a join() issue
diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index 7490639..b99d4c6 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -343,7 +343,7 @@
 		$this->_track_aliases($table);
 
 		// Strip apart the condition and protect the identifiers
-		if (preg_match('/([\[\w\.]+)([\W\s]+)(.+)/', $cond, $match))
+		if (preg_match('/([\[\w\.-]+)([\W\s]+)(.+)/', $cond, $match))
 		{
 			$cond = $this->protect_identifiers($match[1]).$match[2].$this->protect_identifiers($match[3]);
 		}