The standard square root function is supported, generating SQRT (expression) and returning a value of type float. When dragging a Square Root into a variable, the following tree element is created.
Variable Creation > Input > Variables: SQL Elements pane - Arithmetic > Square Root
Columns and/or other expressions can be moved over the (empty) branch of the tree. Note that expressions that resolve to a negative number will result in SQL errors.
There are no special properties for the Square Root function.