The standard minimum function is supported, generating MIN (expression) and returning a value of type matching the type of the expression. When dragging a Minimum into a variable, the following tree element is created.
Columns and/or other non-aggregate expressions can be moved over the (empty) branch of the tree.
The option to compute the minimum over distinct values only is provided, resulting in the generation of MIN(DISTINCT expression). This option is enabled through the Properties panel. Double-click on Minimum, or highlight it and click Properties.