Optional Filter Input (Can be Left Blank or Partial) using Textbox

[nafong]

Using Filter and a Text Box tool to update a dummy groupid and dummy first name, the workflow looks as so:

Input Tool --> Filter Tool (1) --> Filter Tool (2) --> Output Tool

I want the Filter (2) to be optional. If the field is left empty using the textbox tool in Designer, I want it to return all entries of just the inputted Group ID (Filter (1) is mandatory).

If not, if it contains "A", I only want it to return anything that starts with A onwards (should not return Mackenzie if I use smith1234, but should return Adam and A-Mack)

Group ID	First Name	Last Name
smith1234	Adam	Smith
smith1234	A-Mack	Smith
smith1234	Adam	Smith
smith1234	Mackenzie	Smith
sam4321	Petunia	Sam
sam4321	Petunia	Sam
pan99	Peter	Pan
pan99	Peter	Pan

I have attached a sample workflow. Thank you! 

[binuacs]

@nafong one way of doing this

[OTrieger]

@nafong 

Click on Custom and then write the needed condition using IF formula.

[nafong]

@OTrieger I did not know you can use formulas in your Filter Tool! Could I have a bit of guidance in using Custom formulas in my filter? I'm not able to make a reference to the column name [First Name]. 

Thanks