I have found a frustrating quirk in the Unique Value search in the SQL Expression related to the Select Layer by Attribute tool, ArcGIS Pro v2.2.3. You have to know the letter case (upper or lower case) of what you are searching for otherwise no results. This was not an issue in ArcMap, letter case did not matter for results. I don’t always know the case the attributes were entered with, especially in unfamiliar data sets. This needs to be addressed.
Ex) Lower case v = no results Upper case V = results