Revert "Remove unnecessary return"

This reverts commit 96901ff3849c19351c7382689e6a970629586aae.
diff --git a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
index 5d74f57..98ac89f 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
@@ -113,7 +113,7 @@
 
 		if ($prefix_limit === TRUE && $this->dbprefix !== '')
 		{
-			$sql ." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
+			return $sql." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
 		}
 
 		return $sql;