That is how you convert the string “09/04/2018” into a datetime variable, yes. However, you want to ensure that the CSV file is being read by uipath as datetime variables, and that the datetime coming in is in the correct format.
To check if it is coming in as a datetime, read the CSV to a datatable variable, then in a write line activity put:
This will tell you if it is reading it as system.datetime or system.string
If it is string, then you will need to create a new column as type datetime, loop through each row and use datetime.parseexact to assign the newly created column as a datetime (parsed from the old date column). Then delete the column and rename your column to the old ColumnName if you choose.
Now you have a datetime column and you can prepare the filter as specified above. Be sure to include the number sign (#) before the date in your Select statement which signifies that you are comparing a datetime value.
If the datetime is getting converted in the wrong format, try the actions that I mentioned in my above comment to alter the cultureinfo before reading the CSV, or if that doesn’t work then alter the CSV directly before reading it in as a datatable.