Missing Operators at OSLC-Queries using OSLC 2.0

In our understanding of OSLC 2.0 a query is similar to build like SQL.
For writing OSLC-queries it is neccessary to proof values for empty and also for a value.
It is also neccessary to negate those queries.
Actually there are a lot of restrictions in OSLC 2.0,
so that it is not possible to write such queries.

1. Querying for an empty field
Actually it is only possible to ask for an empty field with only on syntax:
cq:Type IN [""] is working.
But other variants of spellings are not working, like:
cq:Type IS NULL (returns a syntax-error
cq:Type = "" (returns a syntax-error)
cq:Type="" (returns wrong result; always 0)


2. Querying for a not empty field (field has any value)
Actually it is not possible to make a query in OSLC 2.0 and ask for a field with any values.
There is no placeholder defined like:
cq:Type=* (returns a syntax-error)
cq:Type = * (returns a syntax-error)
cq:Type IN * (returns a syntax-error)
cq:Type IN [*] (returns a syntax-error)
cq:Type IS NOT NULL (returns a syntax-error)
cq:Type != "" (returns a syntax-error)
cq:Type!="" (returns wrong result)
One command will also return wrong values:
cq:Type!=""
In this case the exclamation mark will be ignored.
The result is all records with an empty Type.

3. Querying for a field, which has not a defined value
Actually it is possible to query for a special value of a field.
But it is not possible to query for a field, in which one value is not defined:
cq:Type != "Software" (returns a syntax-error)
cq:Type!="Software" (returns wrong result)
cq:Type NOT IN ["Software"] (returns a syntax-error)

We would like to have those operators as well in OSLC-queries of the version 2.0.
We need the following operators to work with OSLC:
- possibilities to query for empty-values
- possibilities to query for not empty values
- possibilities to query for not a defined value

Having spaces in front and after the operators should also work well.