TYPO3 Core

The following entry in /TCA/Overrides/sys_category.php in an extension:

  $GLOBALS['TCA']['sys_category']['ctrl']['sortby'] =''; 

removes the field sorting from the sql definitions of the table sys_category. This results in a message in the datebase analyzer:

ALTER TABLE `sys_category` CHANGE `sorting` `zzz_deleted_sorting` INT DEFAULT 0 NOT NULL

Of course if you do so, TYPO3 will crash because the sorting field is needed for all database operations with sys_category.

The problem occurs if you want to change the default sorting of sys_category e. g.:

  $GLOBALS['TCA']['sys_category']['ctrl']['sortby'] = null;
  $GLOBALS['TCA']['sys_category']['ctrl']['default_sortby'] = 'ORDER BY title';

default_sorty is only considered when sortby is empty (null or '')

The problem exists in TYPO3 10 and 11.