Can I query based on a date field rather than the postdate? I'm passing along a year as the yearQuery variable.  Later in my template, I am doing this:

{% set eventEntries = craft.entries
    .section('events')
    .eventStartDate('&gt;=' ~ yearQuery)
    .eventStartDate('&lt;' ~ (yearQuery + 1))
    .orderBy('eventStartDate asc')
    .limit(12)
%} 


What I want to do is show all entries for a year based on the "eventStartDate" field - and not the date they were posted.  

So basically, all Events that were on in 2018, etc.

Is it possible to do this within this query or is there something I am just missing since I have been up way too late?  I have a feeling I may be missing something obvious...
This should work:

{% set year = '2016' %}

{% set eventEntries = craft.entries
    .section('events')
    .where(['&gt;=','field_eventStartDate',year~'-01-01'])
    .andWhere(['&lt;=','field_eventStartDate',year~'-12-31'])
    .orderBy('eventStartDate asc')
    .limit(12)
%}