Pass a simple string as a parameter to Mendix dataset

Hi, I want to pass a students surname to the dataset and get back the counts grouped by the surname using mendix dataset  I am trying to use OQL query for the same. But cannot pass String type arguement to the data set Please help. I am new to mendix.
1 answers

You can create a microflow with surname as inputparameter. In that microflow you create a list of surnames. Second action will be a count of that list and pass that count as a result back