CSS3 selector for attribute that is "has ANY value and is not null or blank"

Question

I can't seem to find a css3 wildcard for 'any value not null or blank'.

I have a bunch of divs, some of them have an attribute called data-group-id but not all. I want to find all divs that have a that attribute, data-group-id`, and is not blank.

So for example I have these divs:

<div class="col-md-2 custom_boxshadow" data-role="mergeSelector" data-required="1"></div>
<div class="col-md-2 custom_boxshadow" data-role="mergeSelector" data-required="1"></div>
<div class="col-md-2 custom_boxshadow" data-role="mergeSelector" data-required></div>
<div class="col-md-2 custom_boxshadow" data-role="mergeSelector" data-required data-group-id="55"></div>
<div class="col-md-2 custom_boxshadow" data-role="mergeSelector" data-required data-group-id="55"></div>
<div class="col-md-2 custom_boxshadow" data-role="mergeSelector" data-required data-group-id="15"></div>

As you can see, the last 3 divs have an attribute called data-group-id.

I want to have a selector that finds those three elements. Essentially I'm trying to do this logic

$parent.find('div[data-role="mergeSelector"][data-group-id="*"]')

where * is a wild card saying 'has a value but doesn't matter what the value is'.

Is there a selector that exists to accomplish this? I can't find anything on the internet.

Thanks!

---

Thank you for the help, finished query is as follows:

$parent.find('div[data-role="mergeSelector"][data-group-id]:not([data-group-id=‌​""])')

Answer 1

[data-group-id]:not([data-group-id=""])

This will select an element that has the attribute, as long as it is not blank.

Answer 2

You wrote:

...where * is a wild card saying has a value but doesn't matter what the value is.

Here you go:

div[data-group-id] { ... }

From the spec:

6.3.1. Attribute presence and value selectors

[att]

Represents an element with the att attribute, whatever the value of the attribute.