DMQL2 Query Syntax for PHRets v2 Seach() to include filter arguments?

(It's been a while since I've been here.)

I've been using the first version of PHRets v1 for years, and understood it well enough to get by, but now I'm trying to understand the advantages of v2.6.2. I've got it all installed and the basics are working fine. My issues are pretty much with comprehending fine points of query syntax that goes into the rets=>Search() statement. (I'm much more familiar with SQL statements). Specifically, I'd like to have a query return a list of properties, EXCLUDING those which already have the status of "Sold".

Here's where I am stuck: If I start with this

    `$results = $rets->Search('Property', 'A','*',['Select' => 'LIST_8,LIST_105,LIST_15,LIST_19,listing_office_shortid']);`

That works well enough. BUT I'd like to fit in a filter like: "LIST_15 != Sold", or "NOT LIST_15=Sold"...something like that. I don't get how to fit/type that into a PHRets Search().

I like PHRets but it is so hard to find well-organized/complete documentation about specific things like this. Thanks in advance.

Solution

As in my comment above I've figured out that the filter goes in the third argument position ('*', as in the original question). The tricky thing was having to find a specific "sold" code for each class of properties and placing it in that position like so: '(LIST_15=~B4ZIT1Y75TZ)', (notice the =~ combination of characters that means "does not equal" in this context). I've found the code strings for each of the property types (not clear WHY they would need to be unique for each type of property: "Sold" is Sold for any type, after all) but the correct code for a single-family residential property (type 'A' ...at least for the MLS in which I have to search is:

$results = $rets->Search('Property', 'A','(LIST_15=~B4ZIT1Y75TZ)',['Select' => 'LIST_8,LIST_105,LIST_15,LIST_19,listing_office_shortid']);

(again, the code to go with LIST_15 will be different for the different types of properties.) I think there is a better answer that involves more naturalistic language, but this works and I guess I will have to be satisfied with it for now. I hope this is of some use to anyone else struggling with this stuff.