[Support request] Select all in category except for posts with some characteristi

Tom and colleagues,

I’ve got a situation where I want to pull all the posts in a category except for those with some characteristic. I’ve tried explain specifically below what I want with two pseudo SQL statements. I’d hoped that I could use the fact that all the posts which are tagged ‘bar’ also have custom meta field ‘Moo’ using ‘not exists’ but that it doesn’t work the way I expect in either the beta version or the previous.

I want to show all the posts in a category, say ‘foo’ except for those tagged with ‘bar’

SELECT * …
FROM “Posts”
WHERE ‘Category=’foo’ NOT Tag=’bar’;

Or, perhaps similarly show all posts in a category, again ‘foo’ except for those where the custom_meta_field exists(‘moo’)

SELECT * …
FROM “Posts”
WHERE ‘Category=Foo’ NOT Exists(‘Meta field Moo’)