Hey @suzi123
It's a little difficult to diagnose the exact issue without a screenshot or workflow, but my best guess is you don't have an action set up correctly.
1. You're going to want to create a connection from your control parameter to the lightning bolt anchor of your filter tool, which should automatically add an action tool.
2. Within the configuration of that action tool, you're going to want to open up the menus until you get an option to change the current value in your filter. If memory serves this will say something like 'Expression - value =' followed by your expression.
3. Then you're going to want to tick the box at the bottom of the configuration menu that says 'Replace a specific string', making sure it's only the value you're replacing within the formula (ie the batch), and no other parts including the ' ' as well.
This means that when your control parameter is being batched in, it will replace and update the value in the filter.
I don't have access to alteryx right now to mock something up but if you still need some more guidance tomorrow I should be able to help if nobody else has.
