Attached is a patch that fixes this by using the following syntax-propertize-function:
(set (make-local-variable 'syntax-propertize-function)
(syntax-propertize-rules
("\\(/-\\)" (1 "."))
("\\(-\\*\\)" (1 "."))))
Adds sql-mode syntax propertize rules to fix comment highlighting
Fixes the issue where -* and /- incorrectly starts comments
in SQL mode Bug(#35646). This is done by adding a
syntax-propertize-function to sql-mode.