diff --git a/mysqltuner.pl b/mysqltuner.pl
index 0e4c043..ec90123 100755
--- a/mysqltuner.pl
+++ b/mysqltuner.pl
@@ -2411,7 +2411,7 @@ sub check_storage_engines {
         }
         $result{'Tables'}{'Fragmented tables'} =
           [ select_array
-"SELECT CONCAT(CONCAT(TABLE_SCHEMA, '.'), TABLE_NAME),DATA_FREE FROM information_schema.TABLES WHERE TABLE_SCHEMA NOT IN ('information_schema','performance_schema', 'mysql') AND DATA_LENGTH/1024/1024>100 AND DATA_FREE*100/(DATA_LENGTH+INDEX_LENGTH+DATA_FREE) > 10 AND NOT ENGINE='MEMORY' $not_innodb"
+"SELECT CONCAT(CONCAT(TABLE_SCHEMA, '.'), TABLE_NAME),cast(DATA_FREE as signed) FROM information_schema.TABLES WHERE TABLE_SCHEMA NOT IN ('information_schema','performance_schema', 'mysql') AND DATA_LENGTH/1024/1024>100 AND cast(DATA_FREE as signed)*100/(DATA_LENGTH+INDEX_LENGTH+cast(DATA_FREE as signed)) > 10 AND NOT ENGINE='MEMORY' $not_innodb"
           ];
         $fragtables = scalar @{ $result{'Tables'}{'Fragmented tables'} };