Dynamically choosing a SQL expression parameter in Model Builder?

[EnvironmentalIntelligence]

I have a working model in Arcmap 10.3 that creates a feature class data from CSV file, queries the data according to a SQL Expression, and then conducts many spatial joins.

The model works as expected, but I want to make the SQL Expression as easy as possible for users to enter who do not know SQL.

How can I make the Query Builder window for this parameter reference the feature class so that the user can use the "Get Unique Values" button rather than entering field names?

As it is currently, the Query Builder window has no fields to choose from, which leaves it up to user to know the field names and correct SQL syntax.