Hello rajeevy89244319
Try something like below where the first operand indicated the path for your NOT criteria, second operand is for the path you wish to query, and third operand is basically a property to query.
select * from [cq:PageContent] where (NOT isdescendantnode([/content/we-retail/ca/en]) AND isdescendantnode([/content/we-retail/])) AND [jcr:title] is not null
Best Regards,
Aneet Arora