26.4.5.22 The version_patch() Function
          This function returns the patch release version of the MySQL
          server.
        
            A TINYINT UNSIGNED value.
          
mysql> SELECT VERSION(), sys.version_patch();
+------------------+---------------------+
| VERSION()        | sys.version_patch() |
+------------------+---------------------+
| 5.7.24-debug-log |                  24 |
+------------------+---------------------+