Fix #4884

1 files changed, 1 insertions, 1 deletions

diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index 5491b2000..5a86ce50f 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -679,7 +679,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 				// value appears not to have been set, assign the test to IS NULL
 				$k .= ' IS NULL';
 			}
-			elseif (preg_match('/\s*(!?=|<>|IS(?:\s+NOT)?)\s*$/i', $k, $match, PREG_OFFSET_CAPTURE))
+			elseif (preg_match('/\s*(!?=|<>|\sIS(?:\s+NOT)?\s)\s*$/i', $k, $match, PREG_OFFSET_CAPTURE))
 			{
 				$k = substr($k, 0, $match[0][1]).($match[1][0] === '=' ? ' IS NULL' : ' IS NOT NULL');
 			}